For the record.... I think the issue is the 40r18..... i have 40 profile on my 17s, and that is ideal for an MR2.
If you're going 18s, you really should be using a 35 profile. It will be more expensive, but it will prevent these sorts of issues.
I made that mistake with 50r16s too. They scrubbed bad....
Looking forward to seeing how this pans out Alex and Josh... any idea when you might do it?