How and where to go when upgrading a BMW?

I've been looking on websites and I am really wanting to do this and not just buy a faster car. I wanna make one faster. Any ways I own a 1999 BMW 323i and the motors an e46. I was wondering if anybody knew of some great sites to buy from that have turbo kits, cold air, chips and the right ones.|||Please don't install the kit yourself if a BMW does not come with a factory installed turbo kit don't buy one off line go to the dealer OR a certified european mechanic shop. Any where else and i guarantee your car will never work right again. This car isn't a chevy or a crappy toyota they are priced so high for a reason the engineer work on these cars is unmatched. also you are looking at about 9 thousand and up to have this done by a Professional.|||go to a customs shop theyll order and install what u want and even if u do get the parts i doubt ull no how to install it most places do mechanics|||dinancars.com,check it out