AS said, track day tyres are much better re grip. On my standard i5 inch cosworth wheels I have Toyo 888 215/50/15 on the rears which are actually 228mm wide. These Tyres I found to be very good when warmed up.
I now run Team Dynamics Imola wheels 7.5/17 inch with Yokohama Ad08r 215/40/17 tyres and these I cannot rate enough more grip than the 888's at colder temps and not a lot in it when warm.
Being a 7.5 rim the 215/40/17 Yokohama's (which are actually 218mm wide) fit the rim pefectly as they also have high shoulders.
8 inch rims are to wide for our cars as you have to start chopping aches etc if you want a tyres that can protect the rim.


Best.

Happy Xmas.

Tim