Well, I think the 960 comes with the B6304S-2 engine, meaning it is the version that emphasizes torque over horsepower.
Search for '92 cams and install them for more power(you'll be sacrificing the lower end torque in exchange for higher end power.)
If your engine is anything like a normal B5254S, you will need to replace the exhaust system as it is VERY restrictive. Anything aftermarket with 2.5 inches in diameter or up are good. Look for BMW exhaust headers. (I don't exactly know which ones but someone will be in here after me to chime in.) I don't really know about the intake but K&N Filters work VERY well or a modified air box.