18"X8.5" rims ok?

[jcatral14]

I have an 03 325i sportswagon with SP.
Right now it has 17"X8".
How big can I go without having to do any mod(of any kind)?
Can I use 18X8.5 up front( I'm pretty sure the rear is no prob)? I'm worried it's gonna rub.
TIA for any info you guys can extend. :)

[Kaz]

Just make sure it has at least 38mm offset and don't use a tire wider than 225/40. If you want to go 235/40 and/or the car is lowered I'd get the offset up to 42 or more.