think of it this way i have a 260z 2+2 and was unable to sell it for $4200 it has a small rust hole in the hatch and 2 holes near the fuel tank ive grinded the sills back and also extreemly little rust, i could just glass it or bog there rust holes are not even the size of 5c coin, but be carful when buying one mine has next to no rust but at one stage suffered hail damage as i have found out from grinding the body back. my advice to you is to find a 2+2 or 2 seater with minimal rust it will be cheaper in the end to replace runing gear than to fix the body of the car and less stressing
cheers pauly