Funny, 'cos I'm using nitrogen too and that makes no difference at all to the softness: A set pressure is a set pressure regardless of gas used, and the only difference with a nitrogen fill is that it won't balloon up quite so much on track, in which case you simply add more pressure in the first place. If 35 psi is too low for you, try adding +2 psi all round. I was simply passing comment about the best tyres, which seems perfectly acceptable on a best tyres thread. Tbh if you don't want a post being commented on then don't post on the internet.
I actually skipped over the part when you said you need tyres every 5000miles when on the PS2s, as if I had seen that I'd have said you're either doing 5 track days in a year or definitely not driving the car properly. Any better for you? I'm sure it's the former though.
Fine, you win, I'll answer that one for you. 225/45/18 and 245/45/18 in Michelin PS2 and they'll definitely fit. You don't need to go any wider than stock tyres unless you're putting down silly power. If you're that serious about track work then I'd be getting a set of PS2s for the road and then a spare set of track wheels shod in R888s to swap over.
Happy now?