just had a long winded chat with TC regarding this, we came to conclusion that 19's 8" width and offset of ET50ish would be a fairly safe bet.
I ran this in CH's on the ED30 lowered with a little rubing on the front arch liner that is easily fixed.
He ws offered an 8.5 with ET45 and we decided this would probably be pushing a bit clearence wise and could also run into some clearence issues with his coilovers too