If I wanted a faster car for road and track, with only logic involved, and it had to be a mk2 Clio. I'd go with a low pressure build and a diff.
Depends on how many road miles really, personally if its doing a lot of road miles Id want to keep things like the aircon, and for that reason alone boost beats bodies as you can have power and aircon at once.
But for reasons of fuel economy, my personal preference for a largely road based mk2 clio is RS2.