[pbonsalb]

There are a bunch of exhausts available for these cars, in stainless and titanium, ranging from about $1500 to about $8000. Based on my research, none add any noticeable power. Supersprint, for example, tested the stock exhaust and found there was no benefit to making one (though apparently one shop did get it to make one), and concluded that the only meaningful gains were in the turbo header and downpipes. Other exhaust sellers make various claims, but there do not seem to be any supporting dynos. The primary benefit of an exhaust is sound and a little weight savings.

I looked at some of the exhausts for sale and noticed a lot of similarities. There was not much to really persuade me, though sellers make claims about quality and fit and power. I decided that if I was going to buy one, I would get a titanium exhaust for the lighter weight and a valved exhaust for noise reduction if needed. If money was no object, I would just buy an Akrapovic or BMW M Performance for about $8000, but money is a consideration and for that amount, I could buy an exhaust plus a turbo header and an intake, which is what I did.

Alibaba has a bunch of exhausts for the F90 M5. Many of the M5 exhausts you see advertised by various online sellers are basically Alibaba exhausts that have been tested for fit and likely finessed a little. No online seller wants bad reviews, so this makes sense. You pay a premium for the experience.

I bought the CSZ Titanium Valved exhaust from Alibaba for $1800 shipped. It took almost 60 days to arrive, but CSZ did warn me that delivery would take longer than the standard 30 days because the exhaust was not in stock and had to be made. The exhaust came in a box roughly 1.5' x 2.5' x 4.0' and was well packed with no damage. Obviously, given that limited length, the exhaust is in a bunch of pieces and is clamped together. Diameter is listed as 80mm or 3.15" while some other brands say they use 75mm or 3.00" piping. Bigger is better in my opinion and my understanding is that BMW uses 80mm piping.

I roughly assembled it on the floor without clamps to see how it looked. I then dropped the stock exhaust, which is 1 piece. Significant weight difference between the two exhaust. I did not weigh either but would say the titanium exhaust weighs half as much as the stock exhaust.

I have a lift, which made the installation easier. Started at the front and worked my way back, loosely installing the clamps so I could rotate and move around to achieve the right clearance to heat shields and other parts. This took a little fiddling. The CSZ exhaust was not perfect out of the box, but the problems were relatively minor in my opinion. Two clamps were too large and had to be cut down to fit. The rear muffler sits at a slight angle rather than being totally parallel, but you do not notice this because it is under the car. The tips do not tuck in as much as I would like, but the results look to me to be on par with many of the exhaust pictures I have studied. I did have to trim one elbow leading to a tip to allow that tip to recess a little more. I will think about the tips for a while and trim the pipes leading to them if it bothers me.

Interestingly, the exhaust that arrived from CSZ was not the one in the picture on Alibaba when I ordered. The only difference is the location of the X. The one I ordered had the X at the front, where the pipes angle around the transmission. The exhaust I received had the X further back. Honestly, I do not think this matters given that the turbo manifold is a crossover design and the turbos chew up the pulses anyway. You will see both X and H and no crossover designs. I have read that X generally sounds smoother, so my choice was an X, but an H or no crossover should be fine.

The other change from the picture is the section going over the cross brace. It looked in the picture like that part was squashed into a rectangular shape to provide clearance like the BMW exhaust. The exhaust that arrived had full circular tubing that arched up and back down. Clearance is fine.

The exhaust comes with 4 bungs that are unnecessary. I capped them. The only bungs on the stock exhaust are on the primary downpipes. The 4 bungs on the CSZ exhaust are under the car. The CSZ exhaust also comes with 2 valve motors, wiring, and a remote control. I did not use that stuff and instead swapped the BMW valve motors onto the valve assemblies. They fit perfectly. This allows factory integration, and my tune works with that so I wanted to preserve that. However, I did have to unclip the wiring harnesses for the valves and reroute them above the heatshield and down through an opening to the valves (on the driver’s side this required unwrapping several inches of the harness from its sheathing with other wiring to provide enough separate length).

Test drove for a little over 100 miles yesterday. No rattle, no vibration and nothing came loose. In efficient mode with the valves closed, the exhaust is pretty much as quiet as stock, which surprised me because there is just one small muffler in the entire system. Totally civilized, which is what I wanted. My wife would not complain. In Sport Plus mode, my tune opens the valves and the exhaust has a snarl to it. Not a loud, deep, throaty growl, but more of a snarl. Still, it is not obnoxious. Sounds great to me. I like it and was not looking for the loudest exhaust possible.

$1800 shipped is a good deal for the CSZ exhaust in my opinion. Looks like prices have gone up slightly, but maybe there is another brand on Alibaba that is cheaper with shipping. While I did have to spend some time playing around to get the perfect fit and I did have to trim one of the tips, that was not a big deal to me. It might be for the person with more limited skills and it is a consideration for the person paying a shop due to higher labor costs for the fiddling. I paid full price, receive no incentive from CSZ, and encourage everyone to shop around and do their own research in choosing the exhaust that suits them best. Will try to get some sound clips in the next few days.

[M5_1of400]

Thanks for the post, I’m looking at getting the same one, I’m hoping it will sound just like the valtronic exhaust, it look identical in the pictures.

[pbonsalb]

I gave some feedback to CSZ on the minor issues that I found so it is possible they will be addressed. That is what the retail sellers of the Chinese exhausts do — test fit and provide feedback to improve the product. But the issues I found were so minor that I certainly would not pay an extra $2500 to a retailer (plus those guys buy 5 or 10 at a time so they pay less than I paid).

Some retailers are selling for less than $5k, though obviously still more than Alibaba, like this one: https://westcoasteuros.com/products/...IaAlJXEALw_wcB

[LouK]

It looks fantastic in pictures, I am still debating doing an axleback on mine. With secondaries and X pipe it sounds good but would like more sound. Most cost effective would probably be the Mad catback. This one is pretty for sure though!

[pbonsalb]

I think the MAD is available only as a cat back, not axle back, so you pay $1800 for stainless instead of titanium, and can’t use your X pipe unless you cut up the new exhaust — I am guessing the X pipe would fit the MAD. But the MAD has a crossover already so you don’t really need to bother — it’s just an H instead of an X.

The only cheap axle back appears to be the Megan and you lose the valves. There are other axle backs but they cost more, especially if you want to retain the valves. At that point, you will have really hacked apart your stock exhaust — first for the X and then for the axle back. That does not really matter since any aftermarket exhaust will be in multiple pieces.

[LouK]

I would just end up replacing the catback with the mad setup if I go that route. 1,800 isn’t horrible for it all.
Think the main issue is how secluded the cabin in the car is, can’t tell what it sounds like outside. Wife keeps telling me it’s loud enough, she doesn’t have room to talk when her vehicle is essentially straight piped 🤣😂

[pbonsalb]

I was in the same boat - my wife complains if the car is too loud. In Efficient mode, the car seems as quiet as stock to me (I have downpipes). For $1800, I got titanium instead of stainless, my first titanium exhaust and I think it’s great. That said, the perhaps 20 lb difference between titanium and aftermarket stainless won’t matter on a 4000+ lb car. Aftermarket stainless will still save probably 20 lbs over the heavy stock stainless. And the fancy titanium is under the car where few see it so it won’t impress anyone, though that is fine with me since I prefer the sleeper to the attention getter.

[M5_1of400]

Any updates? How do you like the new exhaust thus far ? Any issues/concerns?

[pbonsalb]

I really like it. Incredible value compared to what many pay for titanium. Sounds fantastic in sport plus and barely louder than stock driving gently in efficient. Around 1700-1800 rpm, there is some resonance but I would not call it drone since I barely notice it — only driving gently in efficient could I notice it. I keep meaning to get sound clips and will eventually do so. Honestly, any aftermarket valved exhaust is civilized when needed and wild when you want.

[Kimd41]

Can you make a video of how it sounds please?