Originally Posted by e39_touring

I imagine the smell would be the same as your old e46. In the e53, you're a little farther away, but if the air is stagnant, I can see it wafting up front or to the car behind you with the windows down. Nobody has ever mentioned to me that my car stinks, but it's rarely stagnant around here.



It's definitely a one-person job, not really room for two.



Regarding the CEL, if you don't have emissions, it's very easy - just flash it with the BMW EU2 calibration (can be done using all BMW tools - basically makes the car euro spec). If you do, it's a little more involved as you have to do a custom tune that turns off the post-cat sensors so it doesn't throw a code for those. In either case, the front sensors are still used and the mixture is correct. The rears are only there to monitor cat efficiency and make very minor fuel trim adjustments if the front sensors are a little lazy.