[nzuberi]

Guys, I'm a newbie with tuning and need your advice to flash tune or piggy back my 340. It's a CPO with 15 k miles. I've searched previous posts and seems like bootmod3 seems to be the best.
JB4 also has positive reviews, but seems more erratic. I think both of them are traceable if the dealer wants to find out.
Has anyone had warranty claim issues or other issues on bootmod3?
Which tune would you guys recommend? Please share your reviews

[B58]

JB4 is probably the safest, but it’s not the best without a back end flash through MHD and that can be detectable. A dealer can probably verify by looking at certain logs and parameters that a car is over-boosting with a piggyback so if you’re going to tune you might as well just go HAM and jump on the BM3 ship, Mission Performance, MHD (still in closed beta), or you can join my loaner boat running the JB4 with MHD back end flash to control boost and meth.

[kern417]

I recommend a flash tune or no tune at all. No harm in waiting. I did. But I wasn't going to settle for a piggyback because I'm under warranty. A flash will be worth it, but with JB4 you'll just be ready to upgrade again.

[track.n.trail]

I recently flashed my 340i with BM3. CPO also with plenty of warranty left. I agree with kern417 that its safer for the car to run a flash tune. You also get more customization and better drivability.
Servicing shouldn't be a problem, easy enough to flash back to stock and undetectable at a dealer level. If you have a serious warranty claim (engine, turbo, transmission) BMWs engineers will find out that you've modified the car, whether you're using a flash or piggyback.

[mike@x-ph.com]

Both tunes have their pros and cons , safety is not a concern with either one as they have been proven to be safe by thousands of users.

Most of our CPO customers go with the piggy, im using BM3 on a leased M4 without any issues.

[Fuel-It!]

Both are good options.

The JB4 uses all the factory flash tables and alters the tuning to operate from different areas of the factory tables. You can make a ton of safe power this way, JB4 has a lot of great features and app, and can be installed and removed easily at home without a trace.

For flash tuning there is BM3 and MHD as the most popular options. They adjust the flash tables directly and by doing that you can do some things that are not possible with JB4, like changing fuel injector timing to make exhaust burbles, or remove the speed limiter. There is also a lot more than can go wrong so if you go the flash route need to make sure it's a well designed flash map. Also once you flash the cars computer systems are all flagged so lease returns or warranty claims might become awkward.

Then of course many of our customers run both. BMS has flash maps posted that are meant to work with our Fuel-IT port injection kit and fueling upgrades so you can run heavy E85 mixtures, large turbos, and support really big power.

[bm3tuning]

Originally Posted by kern417

I recommend a flash tune or no tune at all. No harm in waiting. I did. But I wasn't going to settle for a piggyback because I'm under warranty. A flash will be worth it, but with JB4 you'll just be ready to upgrade again.

+1
Smarter choice is get BM3 now and not pay more in the long run

Originally Posted by dotfiles

I recently flashed my 340i with BM3. CPO also with plenty of warranty left. I agree with kern417 that its safer for the car to run a flash tune. You also get more customization and better drivability.
Servicing shouldn't be a problem, easy enough to flash back to stock and undetectable at a dealer level. If you have a serious warranty claim (engine, turbo, transmission) BMWs engineers will find out that you've modified the car, whether you're using a flash or piggyback.

+1

[celbii]

12.5k mile CPO 16 340i here. Bought the car with 8k on it. Bought BM3 two weeks ago and have no regrets, car drives way better. Hope I have no issues.