People will want a few more details from you, namely model year and what fuel system is there now, as this affects what parts you will need, which ECUs, etc.
All 240s, aside from the early carburettor models, will have a pretty capable fuel system already, e.g if your 240 runs Bosch K-Jetronic, LH-Jetronic 2.2, or LH-Jetronic 2.4, you can use the existing fuel pumps and supply with a +T build. I run 13 PSI of boost on a car that still has a stock K-Jet fuel pump configuration, and it has worked just fine, year after year.
