I am new to this forum and to the BMW experience.

I do not own a BMW yet (2000 Trans Am WS6 until I can buy my M5), but my sister has just bought a 2000 328i.

I am looking to get her some things for her car for Xmas, could you guys tell me of good sites to get BMW quality parts?

Are there any shops in the Chicagoland area that carry these products?

What were you looking to spend there isn't much in performance that is under $500, You could get a intake for $300 or a short shifter for $150, clear corners all the way around will run about $500 as well as a chip reprogram.
Look at www.bavauto.com
or www.bmpd.com