I run a 23 solid 3rd gen rear but I also lowered the phb mounts so the setup is a bit different. I did run a 25 solid at the rear for a while using the stock phb mounts and it was confidence inspiring at high speeds, but I could see how it might make the car too tail-happy in sharp cornering situations like autocross. So I'd say if you have a 35 front, give the 23 solid a try, you might like it.

You can't go wrong with Sam's setup IMO. I've had 32 & 35 solid fronts, but the 32 hollow is just right.