it's always better to build up your engine for a turbo setup before just throwing it on ya know? Most of the time when ppl boost a none stock turbo'd car they rebuild the block with new upgrade stage internals bearings, crank work, pistons, etc. Also the head can be upgraded with upper stage Cams and valves/springs made for turbo setups.
Yes it's all expensive but it's VERY much worth it. But if I were you I'd start off basic and simple and upgrade wheels and suspension and then go from there. Remember though don't be cheap on performance stuff suspension,internals,exhaust even. If you have to save a lil longer to get a good brand product do it don't risk bying junk that won't last.