I know its been asked many times but I can't get my head around this offset drama. I can get some H&R pcd adaptors here in Dubai, to adapt 5x112 wheels to fit 5x100. So what I would like help with is the offset I would need for 18" 8J wheels to sit flush with the outside of the S3 wheel arch, with the 20mm adaptors fitted. From what I have searched for and tried to calculate on the wheel offset calculator, I need wheels that are 18" 8J et45. Does this sound right?