most i think u could do would be decat and exhaust .... its not gonna sound like an e30 325i though... and gains would be minimal .. maybe just for the roar .. anything else i feel may just not be worth the money spent ..
ive removed the cats on my E92 and changed the stock air filter to a BMC performance filter, i can feel a difference the car feels a lil more responsive, and tones better at the same time my fuel consumption has improved. :rollsmile:
Yes I agree a supercharger will do the trick but the price you can buy an 330i and even a newer model. don't expect miracles to do a bit here and there. the best you will gain is better drive ability. Good luck