I did it on an old mk1 gti, you can use any bigger throttle body, but i was told to use the matching warn up reg from the same donor engine.
The inlet manifold has to be opened up so the ports match.
A vacuum hose needs to be connected to the warm up reg so the fuel is enriched on full bore.
Drill your air box and get a K&N-you will really notice the difference!

Any further help needed-get in touch