When I had my m326 wheels on and lowered on Eibachs I believe it was a 12mm spacer I ran on the rear. Much more and it would scrub badly on the arch liner. This was also with a 255/35 tyre.
A 12mm front spacer is absolutely perfect but you won’t be able to push the rears out enough to match so I ditched the front spacer all together.
I now have different wheels which are wider so no need for spacers and switched to h&r front springs to get the front end down some more.
I'm running 12mm rear (hub centric) and 3mm front (wheel sits on hub lip no problem). Car is lowered on Eibachs. Front and rear bolts are all new and longer by 12 and 3mm.
The front and rear arches extend the same distance from the wheels/tyres so look spot on.
SteveSmith (and others) gave me lots of advice and I'm happy with the way the car sits. I've yet to update my forum sig though!)
thanks for that the car is not yet lowered , I have not yet got my head around which wheel is which will find out and check. I would also appreciate some advice on best kit to use to lower and by how much cheers