Hi all,
It's time to upgrade my track wheel/tyre combo.
I'm  currently running std. 15" rims with Toyo proxes R888 205/50R15 on the front 225/50R15 on the rear
The new wheels I have picked out are 17x8 +35 and 17x9 +35
I'm also looking at Dunlop DZ03G's to put on these rims. The question I have is will 255/40R17 fit on the rear and also will 225/45R17 fit on the front?
My tyre guy was thinking to put a softer compound on the front which is not available in 215/45R17 which is what I was planning to run with.

On the rear, 17x9 +35 with a 255/40 tyre should fit. You will probably have to rolled the inner lip on the guard to avoid rubbing issues though.
I would go 215/40/17 on the front. I had a 215/45/17 tyre on the front of mine and it rubbed on full lock and high speed bumps. My car was lowered on coilovers though.

Unfortunately they only do 45 profile in 17s until around 245 where they drop to 40. So if your 215 45 rubbed I've probably got no hope of fitting 225 45 then

is the car lowered? yeah 225 45 17 wouldn't be a great idea. It may work with the occasional scrub

King springs with koni shocks

255's no issues on the rears. 225/45 will not fit easily.
 
a 225/40 barely fits as it is.
 
Have you considered the 215/40/17 Federal RSR? they're a softer compound tyre and a lot of people on this forum have had very good experiences from them.

Not really the type of tyre I'm after. the dunlops are one of the top Tarmac rally tyres around at the moment and I'm wanting to upgrade to a better tyre than the toyo r888 that I currently use