Not sure about the Carlton but omega offset is practically the same
my old 19's I brought as a vectra c fitment, my steel wheels I use are from a vectra c and my mate has vectra c gsi wheels on his omega.
Can fit between 35-42 on both the vectra and the omega without any issues
Omega is et38 and vectra et41. I've never been able to notice that 3mm difference
All the models vary too. The omega irmscher sport stars are et30 from the factory. I've fitted et40 on the rear of mine to allow for the 9.5j rim sticking out
offsets mean nothing as long as its not a massive difference
Can't be much different to the Carlton ? Either way they will fit, spacers are always available anyway
