i have a 2003 chevy trailblazer. which unit (or link me a different one) thanks for the help guys!

http://www.logjamelectronics.com/neucncx2i.html (this doesnt have my year but ive read a few spots it is compatible)

and

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=170146564577

ps. new 160GB tom :)