Thanks everyone! So what do you guys prefer in terms of tire size? Larger section width or taller sidewall? I assume that the larger section width probably results in better/more road contact and the whole "driving on train tracks" feel vs. a larger sidewall probably makes for a little more comfortable ride but some tire folding in sharp curves? Overall, with a stock Golf TSI being the vehicle, I would probably tend to the larger section width since there's only so much "racing" I can do with it, but happy to hear y'alls thoughts.
As someone who autocrosses a mk4 Jetta wagon with the 8v -- don't ever let anyone tell you that you can't race it. Just do it in a safe and law-abiding manner.
Regarding sidewall height and whatnot however, I would stick with as close to a similar outside diameter as you possibly can. If the stock tire for your car is 26" diameter, try to shoot as close to that as possible -- a tire size comparison calculator like
https://tiresize.com/calculator/ will work just fine. Personally, I try to run a decently meaty sidewall (225/45/18 on my GTI) and stiffen things up with sway bars, since you lose very little ride quality that way but can greatly improve handling. Sidewall flex is going to vary between different models of tire as well, so you will want to bear that in mind -- you could in theory for example, have a 225/45/17 be softer than 225/50/17, if the larger sidewall tire is more track-oriented.
In any case, with two sets of wheels, you arrive at what I consider a wonderful place: the land of options! Try out tires, see what you do and don't like -- and check out your local SCCA region
