Be VERY leery of the 'performance chip' claim, there is no such thing on a C5 Corvette. Tuning's all done with a Tech2 unit or a laptop and some software like LS1Edit and a few others out there that come with the cable to connect to the onboard computer.
You have the right idea on the hardtop if you plan on some track days. Most organizers require any verts to have a roll bar installed.
Also pay attention to what they mean by 'exhaust system', it's probably a cat back so you'll be wanting some long tube headers and a decent X pipe on it before long. Trust me. I swear to God I'm gonna stop tweaking my 99. Yeah, right.

Just make sure the recalls are taken care of. Biggies if I recall right are the seat belt retractors, the steering lock and the driver's side diff seal that was prone to leak until they re-engineered it.
There's an 04 in Vancouver on Craigslist for 26,500 right now, didn't look at the miles though.