Quote:
Originally Posted by M3-S65
X pipe has the main cats on it...so it will throws codes too. Also to remove the X pipe you have cut the exhaust to remove just that section....Mother BMW will not miss that when they see those clamps.. and codes....LOL. Plus limited to no HP gains from the X pipe, On top of that I heard when you remove the cats (either primary or secondary) you can smell the exhaust in the cabin. The smell is only half of it ...you can imagine what your doing to yourself physically if your smelling that poison crap at a stop sign and red lights....not to mention your kids/wife/girlfriend etc etc......
NOT trying to be a killjoy, although I know I am being one...  but these are things that stopped me from modifying the exhaust - except for axel back... If someone want to chime in on a system that does not throw codes perhaps by using high flow cats in both positions with perhaps defoulers so no codes are thrown at all......and does not stink up the cabin with poisonous exhaust gases...I would buy it...pretty sure something like this would have limited gains making it essentially a waste of money...I already wasted enough money on an Axel back that did nothing for performance... 
I used to own a car that we would put a defouler on the exhaust where the cat went, so we would not have to program out the codes. So that Dodge did not know and so that we kept our warranty. This essentially fooled the system and Dodge.. I hear nothing about defoulers on here...probably because the Engine Control System MSS60 is so advanced you cant fool it. http://www.modernperformance.com/pro...aliber_exhaust |
Wow dude, your are putting a lot of misinformation out there:
An x-pipe requires no cutting of exhaust parts. The stock x-pipe drops right out and most aftermarket pipes bolt right up.
I am running test pipes and do not smell the exhaust inside the car... my secondary cats are still functioning... I guess this is somewhat subjective, but I just don't smell it... don't smell it with the windows up, don't smell it with the windows down...
I also think you are probably being a little paranoid about the check engine light / warranty... If you ran a delete R, and needed to have warranty work done, I imagine you could remove the delete R and reinstall the stock x pipe and then BMW would just think you had 2 bad oxygen sensors...
Deleting the primary cats on the M3 is the biggest power gain mod you can do short of a super charger.