The Regulations are very "simple". All you need is original engine with original 70,0mm pistons, original cam,original head, all original. What you can do is replace gears and diferencial ratio from the uno 1301cm3 Ds or 903 cm3.
Koni shocks and this year with the same springs to everbody. Last year only the springs made 3sec diference Between the cars. That springs that same cars used cost 1000€!!!!!.
I can put the Regulations here but they are in portuguese, if you can translate it I have no problems to post it