Probably to a certain extent. I'll do it because I quite like the idea of the engine coming out and everything having a good look over, bay detailed, that sort of thing. May as well do the belts at the same time. Belts wise I could well be wrong but think they are Dayco belts, so pretty much the same as are on loads of other cars with ever so slightly longer belt change intervals.
Sorry to burst a well thought out bubble...but a belt sitting on a shelf for 5 years won't look the same as a belt stretched out over 4 cams (or 2) for 5 years. All that tension makes things stretch locally, so it could skip a tooth when that stretched portion feels the stretch of 8500 rpm torque / shifting. Don't get me wrong, I don't subscribe to 3 yr changes, I'm going for 5 on mine. But 5 yrs on a shelf in a box is much different than 5 yrs stretched in the engine.
Yes. There are several manufacturers of these, I believe Cosworth is one. Don't know if Kevlar is an acceptable application for these cars though.