I am a TW head kinda guy so that is where I would lean to.
As for a cam, for a few more bucks I would go with a custom cam. Better idle (good for automatics, ac and other things) drivability, power across the powerband etc....
There are no hand held tuners for our cars so someone would have to burn a chip for your car.
And lastly gears are subjective as the steeper gears will get you going faster but hinder your mpg somewhat. There are a couple of calculators out there that will show how many rpm's you are spinning in 4th gear to give u an idea. So anywhere from 3.55 to 4.10 will be a good choice.
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