Recommendations on performance and sound upgrades? Looking at Ingen Air Intake System $300 vs M Performance Exhaust $1,100.
With seemingly infinite upgrades & performance options for all variety of bimmers, getting specific about desired end results can be helpful before jumping into that particular rabbit hole. A whole bunch of money later and you come out with a car that's so modified it's nearly impossible to drive on the street. What's the goal? HP gains? Sportier sounding exhaust/engine? There are advantages & disadvantages to whatever one can change, understanding comparisons & defining goals & budgets can help shape a plan to get there. Mods from BMW of course should be a seamless compliment to the car, but may be more expensive than other aftermarket perf. exhausts. Sounds like you're not talking stereo/audio, but if so - https://www.bavsound.com/