Suspension: Lowered just on springs, was done before I bought the car.
Engine/Drivetrain Modifications:
Not sure what was done before I bought the car but I have not made any changes it does pull away from most other E90 320D's and with cruise control on at 70mph I get between 66-68mpg
Exhaust: Twin pipes together, think its straight through with no DPF.
Future Planned Modifications
Would like to upgrade the iDrive, mine is the old version also with a small screen, has Navigation and Bluetooth for phone calls but can't play music or anything.