The interior looks nice in the picture you posted. I still don't think it's on par with your M3. If you really like the car then buy it. I think you should wait as the C7 will soon be released. The C7 interior is allegedly a huge focus for GM and is supposed to rectify what is considered to be the Corvette's biggest weakness: The interior.
The interior you posted looks nice but at 90K I would expect a little more. Don't' forget that the seats in the C6 are a common complaint from many automotive magazines.
The outside of the car looks fantastic. It sounds like your driving a volcano. Tough decision. Good Luck!