I have an '06 STI and had a similar dilemma a few weeks back, ended up with the following combination;

18x8.5 +30 with 225/40/18 tyres.

Rims cleared Brembos with ease and the tyre and rim combination was the closest rolling diameter to stock so speedo runs near perfect.

I'm running a bit of camber and guards haven't been rolled, rims are tucked under and sit nice and flush without any poke.

EDIT: Some sh*t photos for reference.

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