Just to add my 2 cents' worth to the thread, I went with 20mm, pretty much identical to what
@D.J. showed (down to the foam "spacer" packaging) but with black hardware.
On a 2022 AWD GT2 with 19s, I had no issues with fitment, rubbing at full lock, or steering articulation. My install process was:
- remove wheels, lightly rub wheel mounting surface of rotors with sanding block to knock down the bit of surface rust where the wheels contacted them, wipe clean of residue with 3-in-1 oil on rag
- test fit spacer and wheel, confirm no movement radially (ie hub does in fact center spacer to rotor and wheel to spacer), drop car, move steering lock to lock to confirm fit
- remove wheel and spacer, thin coat of anti-seize on back of spacer, small amount of blue Loctite (243) on factory studs, install spacer to hand/drill tight
- for fronts, be sure jack is stable (ie backup jack or jack stand) and wedge wrench/board between studs and ground since you have to fully torque in the air
- torque spacer nuts to 50-60 ft-lbs, then 85 ft-lbs
- mount wheel, put lug nuts on hand/drill tight, drop car, torque to 50-60, then 85
- repeat on other 3 wheels (but no need to repeat step 2)
- test drive (slow roll with windows down for sound/feel, then at speed for any vibration from non-concentricity)
Probably spent 45min on the first wheel with the test fit and re-install etc, then maybe 15min apiece on the other three. While there wasn't any play radially (up/down/left/right), the spacer hole tolerance around the studs allowed a little bit of rotation, but when I held the spacer turned to its limit in one direction (maybe a degree/couple mm), hand tightening a nut would pull it back to center.
I'm happy with the look and didn't feel anything different on the test drive -- no vibration, no change in low-speed steering effort, etc. Haven't done any aggressive driving yet.