if you go on ebay you can pick up a set of r1 throttel bodies for 50 to £80
get a inlet manafold bracket made and if you want loads of bhp get a DTA ecu not cheap but the ecu itself can hold upto 300bhp plus and it controles everything

and you will need make a wireing loom for your car to go in the ecu sounds hard work but not that bad my mate use theses set up on their kit cars /westfields

you should easy pull 40 bhp plus