18x7.5 & 18x10's for track yes or no??????
 

7.5JX18 et 50 Part number 993.362.134.06, and the Rears are 10JX18 et 65 Part Number 993.362.140.04

they are dirt cheap, are they worth having as an extra set for a few hundred bucks? I know they will probably need spacers but I can have some sturdy cheap wheels for the track.

Why not? ..

I have heard unfavorable things about spacers on track wheels.

No

I can understand someome reducing wheel from 19" to 18" and to be honest most would track with 18's anyway, but you would never remove width! You need as much traction as possible on track.

Spacers get bad rap. Almost all RUF wheels us esome king of spacer. Some over an onch thick. Really, what's the difference between a wheel with a hub centric spacer or a wheel with a different offset. If it makes you feel better. get the spacers welded on your wheels.

Spacers should not cause any problems.
Had mine fitted by dealer(6mm f and 15mm r) and runs fine on both road and track.

No these are 993 or 996 wheels. That's why they are so cheap.
Your car needs 8 front 11 rear, at least. the GT2 set up (mine) is 8.5-12 inches.
Yes those wheels would get you around the streets but you would loose performance at the track and the car would handle less than optimal.
The track is not the place you want to cut corners, you are putting huge demands on the wheels, tires, and brakes there and need it all.
As always, my 2 cents based on my car wheels, your results may vary!..tom

I trust your opinion enough to go with that.