Tires are Continental Control Contact Sport AS. I think they have been superceded by a new model.
Springs are from Tiguans front and rear, front is what most people use (2wd) but rears are a specific Tiguan Spring (slightly shorter and stiffer than JSW Towing springs). Front struts are Jetta Koni SA and rears (for now) are Tiguan 2wd Koni SA. Also have a GTI 21mm rear sway bar.
Tiguan Front Springs - 5N0411105T
Tiguan Rear Springs - 3C0511115AG
GTI/Passat 21mm Rear Sway Bar - 1K0511305CM (buy used and get some new bushings!!!)
I bought genuine OEM springs from a dealership, not the Suplex copies. The result is a little firm in back (but not harsh), but if you carry a lot of weight in the rear often, I'd recommend it. I'm planning to replace the rear struts with Tiguan Bilstein Tourings (B4) to see if that softens it slightly. I tried using Jetta Koni SAs and they were too soft, plus they clunked over large bumps.
I went a little different route with the rear springs and sway bar to reduce understeer. I think it was successful, it's not like a GTI (it leans) but I can accelerate around a turn and the rear will follow.
Gas mileage probably affected slightly, but not much. Maybe 1 mpg. I get about 30 city and 37 highway going about 70 mph. Speedo is now only 1 mph off but odometer is about 2-3% lower so you have to adjust mpg calcs.