Wheel fitment question - XXR 527 (Sigh...I know)

I know this is one of those annoying questions people ask all the time. I've used the search, done googling and tried to use calculators but wanted to make absolutely sure before I commit as I'm a little confused to be honest.

I've got my eye on some XXR 527s and wanted to check the fitment. Now I've found Rich's thread (link below) that says he was running ET20 all around on these. So from what I understand they would stick out 30mm more than stock.

http://www.mkivsupra.net/vbb/showthread.php?296540-XXR-527-Bronze-As-New

I'm running stock suspension and body with stock wheels right now.

Also I have UK Brakes.

The fitment I'm looking at has the same sizes except the offset:

18"

Rear 9.75 ET12

Front 8.75 ET30

From the calculator I used it says the rear would extend 41mm more than stock. And the front would extend an extra 23mm. The front I'm not so worried about but the rear seems a bit excessive but is only 8mm more than Rich's example above. Clearing the brakes also worries me.

Is there anyone else running these wheels with similar offset? Would I have an issue? Any help would be appreciated.

Cheers!

I have 527's on my car. +35 front with +20 rear with a 5mm hub centric spacer to clear my UK brakes. I need a heavy arch roll at the rear also. Apart from that no issues at all. Tires are 235/40 front and 275/35 rear.

Cool thanks for the reply, sounds like I'll be all good with an arch roll on the rear which I don't mind.