@midge
All Ph2 ARBs are part number 8200 104 120.
Std PH2 172 rims are ET48.5 & 172 Cup is ET38,which is 21mm right there,which I believe is the difference.
Ph1 & Ph2 std 172 share front wishbones 6000 073 511 & 512,(which are still available).All other 172 & 182 models share front wishbones 8200 257 956/957 with the cup spec castor angle.
I`ll bring some std 172 wishbones when I pick up the wing,and we can confirm there is no difference in the width once & for all.
All PH2 front subframes are the same pn 8200 107 153 on UK spec cars.