I think my 2118s are ET48.
Got mine for £400 new.
172 cup = ET38.5 off the top of my head
182's scrub with that offset though hence the ET43 option (palmersport wheels)
managed to get them for £720 with T1's. not a bad price i thought tbh considering the original price on eBay is £869
£699 from Revolution247.....
I probably need coilovers though for them to look decent
1.2's and 172's do, cup racers ran the ET38 2118 to replace the OZ F1's they originally used (bendy bendy wheels)
I believe European cup racers ran 48.5 these are also Identified as have speed line course stamped into the wheel rather than stickers..