Depending on how much you are going to inject and how often.
If 100 shot or so and you have stock heads then you could use the Autolite 24's which is one step colder or the NGK UR55.
Then you will also have to close the gap some try 45 and go from there.
Also you will play with the timing some.
2016 VW GTI 2.0 Turbo
1989 Sonic Blue LX Coupe, 349 ci, TW heads, TFS Track Heat Intake, 75mm Accufab TB, 80mm ProM, 30 lb. inj, TKO, 3.73, 31 spline w/ TruTrac, MAC 1-5/8" LT headers w/ H pipe, Flowmaster, electric fan Moates QH
391 rwhp & 424 rwtq...Mustang Dyno 11.5@122mph