Yes, believe me, I thought about it (and am still thinking about it). I wouldn't bother upgrading the brakes since I don't really need it at the tracks I run. The wavetrack is $1200 + maybe another $1000k in labor. If I upgrade the suspension, it would likely be ST XTA's coil overs (rebound adjustable and already includes camber plates) $1350 and I would install it myself. So that's $3750. I'd have to upgrade the stereo also which would be a PITA.
If I got the GTI Autobahn+Driver Assistance, I get the adjustable-on-the-fly DCC suspension, active cruise control with lane keep assist steering, better infotainment/Android Auto, Fender stereo, VAQ, and the bigger brakes that I don't need yet but would if I run at Watkins Glen again. The problem is, I don't think there are many GTI's spec'ed with both Autobahn AND Driver Assistance included near me.
If I got the R, I'd get all of the above minus the VAQ, plus AWD, plus an extra 300lbs of weight (250 lbs + euro spare tire set that I will add). But it seems that it's easier to find an R with everything in it that it is to find a GTI Autobahn+Driver Assist.
So it might come down to which used car shows up first in my neck of the woods. I think I'll be happy with either 7.5 GTI or R. It's my daily driver and my "it's-not-too-precious-car-so-I-won't-feel-bad-about-tracking-it" car.