365 GT4 and 412 tires

I've tried the search function and seen a lot of interesting discussions of alternatives for boxers (and the possibility of making larger wheels), but I don't know whether there is an existing tire size upgrade to the 215/70/15s that currently reside on the 365? I was thinking slightly wider, like 225/65/15, which is available at tire rack in the Pirelli P 4000.

On the 412, the Michelin TRX and rim are unique and it seems that Coker is the only option. Would another F car rim fit in that wheelwell? I'd love to put a 456 rim on it, but I suspect the rears would be far too wide for the body.

Any thoughts on either.