That might've been greatest 2 hour read on a plane in some time. Belated congrats on the new ride, been awhile since I've browsed the MKVI forums. :w00t:
I owned both, and without getting scientific maybe seat positioning. I feel the B8 is more reclined, than the GTI which is more upright.
The perception of size and space is greater otherwise.
Do it. I went from a Stage 2 GTI with all supporting mods, and its a huge step up in performance to a B8. Its seriously underrated from the factory, and a tune will turn it up even more.
B8 S4 here. I'm riding on 19" peelers, and the ride is surprisingly compliant. Its definitely firmer than the GTI I had with DG Springs, but still comfortable enough to cruise through all types of roads/conditions.
30k miles, Audi Mission Viejo is where I negotiated the purchase. Literally flew down to pickup the vehicle.
If you're looking locally in Norcal, there is a 2011 S4 with 32k miles at Stevens Creek Porsche. They are asking for 43.6k, but it may still have the remaining CPO + AudiCare (no Stasis...
For sale:
Escort 9500ix (blue) in original case
Brand New Escort Supercup Windshield Mount
Radar detector worked great in my GTI with a hardwired/blendmount setup. Sold the GTI, and unfortunately blendmount does not make a kit for the S4, so I'm going a different route in the new car.
Unit...