I take it you want a cossie lump in it? if so you would still have to declare the engine as a 2.0 16v turbo or you would invalidate your insurance. May be cheaper to insure than a cossie but i doubt it unless you dont declare any other mods, ie bodykit, alloys, exhaust etc, and if you don't declare them see my opening point!

Why not just buy a saff cossie and have the real thing. Genuine ones are not really that expensive to buy. I can see why someone would want a replica RS500 as they are mega bucks, but a replica saff ??? not worth the bother imo.