It's time for me to replace my tyres
I currently have stock tyres sizes, and stock suspension

My wheels are TechArt Daytonas, and the rears have a 25mm offset (!!)

When I hit a bump I get some rubbing on the rear arches
It's not too servere, and I think it would be resolved by rolling the arches

My questions is... Once the arches have been rolled, do you think there will be enough space to fit 315's on the rear?


Rolled arches, 25mm offset, 315's ????

 

That is the correct wheel and tire fitment. You need to roll the fenders and check your alignment. The et25 is an aggressive fitment.

 

+1. A good roll and some negative camber

 

What alignment should I go for on the front and rear?

What should the toe in/out and cambers be?

 

I had that setup on my C4S with the Techart formulas and it was lowered on H&R springs and I never had a rubbing issue. Just and FYI.

315x25x19 et 25

 

For a med. aggressive alignment I would say

0 tow front
.25 tow in rear

-.7 to -1.0 (or max) front camber (minimal tire wear issues in front)
-1.6 to -2.0 camber rear (not much choice on a low car) or as needed to clear

You will like the handeling and braking stability.
Good luck with the rub, remember you will need the good rolling especially with the ps2 tires. They are better but the Continental and Toyo are a little smaller.