Changing tire sizes on an M Coupe?

[CorgiCoupe]

I have been told that the staggered tire/wheel sizes on an M Coupe contribute to understeer. This is quite noticeable doing DEs on the track. Would switching to 235/40x17s reduce the understeer? I'm ready to order a new set of Kunho Ecsta MXs for the OEM Roadstars. :help

[Daved]

I'd switch to 245 all around, I guess you have 8.5" in the rear, get some 8.5" for the front and that's it.