I am looking at a set of 20" rims for my 2007 335i Cabriolet.

I have chosen the Maya RT5's in 20x9 and I think i'm gonna have a 245/35/20 tyre?

Does anyone know the correct offset that we should have to ensure that I will have no rubbing on the arches?

I will also be lowering the car on KW coilovers.

Also anyone recommend somewhere to buy the rims and tyres at a good price?

Thanks

Phantom