The inlet on the 20g is 2.5inches roughly, so get an intake at least that size. I dont think the injen is the way to go, I would do dejon or home depot. Either of those 2 FMICs will work, but I'm partial to the SBR/Kinetic version if you want a real bigass one, the last one you'll ever need. Injectors depends on what managment system you choose. Pump, depends on how far you plan to go in the furture. I would highly recomend a 255 HP with a regulator, either aeromotive like my setup or a bolt on version.
If you have the option of using DSMlink I would highly suggest you go that route. The AFC, logger, and a chip to eliminate fuel cut will cost as much or more as DSMlink. I made money when i went to DSMlink and sold all that BS.
Then you can run any injector you want. I would highly suggest FIC 950s. With the 950s, and the 255HP and reg, you wont have to worry about fuel unless you go REAL BIG. Do it once, do it right. Dont upgrade each part 10 times like I Did. My car would be a lot faster with the money I could have put to better use
Hope that helps.