there was a rare RS/X-pac option of twin 36's these claim to give an instant 60bhp
there were also supposedly a cam and 4 branch but only ever seen one of the manifolds
start off with a good service, if youve got the skill head gasgets are cheap enough to be worth doing
also late mk2's came with electronic ignition if you can get hold of an electronic distributor there alot more user friendly and reliable than points