You'l have to get under the car and have a look at the pipework associated with your muffler. My 325i is 2009, so direct injection. The pipe into the muffler is quite long and has a bolted flange. But I've seen others where you would deffo need to cut (and then weld).
Or have a look in RealOEM for your car:
http://www.realoem.com/bmw/select.do