actually the 99's should be the M52 TU which is a bit different than the M52. And +1 with capelo on the cam sensor, there is 2 an exhaust and intake, the intake will have an effect on how the car drives which will be crappy and also can cause stalling as he already stated. $80 bucks for the exhaust and $95 for the intake. This is a very very very common problem for the E46 and I can honestly tell you I probably do 10+ of them a month. Good luck! and the brake light issue needs to be properly diagnosed but the most common is the brake light switch which most people damage by steping on the brakes too hard and too fast causing damage to the switch.