Realistically I don't think you will get 200bhp from an 8v without turbo or supercharger and other work.
From a 16v you will need headwork, cams, matchporting inlet and exhaust manifolds, individual throttle bodies, stand alone management, remap etc. Cost you about 2 to 3k to do it properly. £300 porting, £300 cams, ITB's £600, management and associated bits £1000, remap £250 all approx.
As Wayne says cheaper and easier to go for a 1.8 turbo lump and have it remapped.
Paul