My race tires are mounted on Millenia's, which are the same as the stock ITR wheels (15x6 & 50mm offset).
The 5mm spacers effectively create a 45mm offset.

I ran the whole season with 225's last year (my first with the car, and the first on race tires), and felt really good about it. You feel the width when driving through the pits, but not when you're on course.
The common setup for DS is 225's on front and 205's on the rear. I also run the 225's on the rear for our local stuff which is on asphalt grip that is not so super.

I hope this helps.