My brother was running Krimson K6 wheels (18x8 ET +40). You would need an 18in rim with a offset in the mid 40s.
Example: An 18x8 w/48 offset (standard LGT rim upgrade) you will need a 3-5 mil spacer. These do take up some room but are worth it.
Thanks for your interest.
'07 Forester STI (ECS Performance)
'10 LGT Limited (Protuned by Chris at EFI Logics)