no idea on the belt part number but ill chime in and give my dash opinion.
1) after sitting in a sk2 with the wheel under the dash bar and over, i would 100% go with the over bar option. first it looks a hell of a lot better, and second you can see the gauges in dash better (my opinion).
2) stay away from any type of reflective surface. my s2k has a machined dash, which does not have a high shine, BLINDS me when the sun is high or behind me. a gloss finish carbon fiber dash will do the same. i advise aluminum with a vinyl carbon fiber look, or a low gloss leather/leatherett with a slight bit of pad to make the gauges look sunken in.
3) keep the fuses on the front of the dash, move them to the pass side. some of us (me) have always had little electrical issues and do pop the push fuses while driving. its nice not to have to get out of the car to push the fan fuse back in.
here is my dash (with the old maiata engine) tach is now positioned at the proper angle.
also, here it is when i first got it with classic gauges (if you considering that look)
http://imagizer.imageshack.us/v2/800x600q90/12/cimg1153i.jpg
http://imagizer.imageshack.us/v2/800x600q90/10/cimg2771resize.jpg
http://imagizer.imageshack.us/v2/800x600q90/132/cimg2762resize.jpg