Hi mate,
best place for a rebuild kit is probably USA, but if you don't depend on your car as a daily driver then I would just strip it and clean it and try to reuse the gaskets that are on it - they should come off in one piece if you are careful. The tiny jets are easily blocked with years of debris and float levels can be checked at the same time - not a difficult job really.
Regarding alloy wheels - choices are limited due to the odd Mazda stud pattern of 4x110mm. I would suggest some adaptors to change the pattern to either 4x114.3 (same as the series 3 model) or 4x100 which is like MX5 - then that opens up a whole plethora of choices. Adaptors can be had quite easily in 25mm width for £100-£150 per set. You can go thinner - approx 20mm but have to watch out for the height of your wheel bolts. The stock bolts on My RX2 are very small so fit under 20mm easily but I haven't tried with a S2 RX7.
Good luck and welcome aboard!
p.s. any pictures?
p.p.s. Codge (Dave) is the resident record keeper of all things 1st gen RX7 so would love to know the reg and any history you have on the car
