Which wheel + tire for track use?

[Mr.Snood]

I'd like to get an additional set of tire + wheels for track days.

I currently have 18" 335/30 at the rear and 18" 245 at the front.

Is 19" at the rear an option?
Is it possible to fit a bigger/wider tire at the front?
What wheel/tire do you use/suggest?

[spatz]

i have a set of factory supplied of kumhos lying around which we had to exchange for f1 because of german tuev. they did a few kilometers testing the car, so they are almost new.
If you want them they should be the right tire for the track at least this seems the common opinion here.
send me a pm then i give you my phone, the few ultima guys in germnay should know each other anyway.