I'm running G015 on my 05 in that size, they fit nice. Your stock offset is 45mm, If you use a more positive offset it's going to push the wheel assembly out toward the street side, conversely a more negative offset will move the rim toward the brake side of the car.
Also take into account stock wheels are 6.5" wide, a 7" aftermarket, say, will push clearances inward toward the brake assembly and eat up another 1/4" but also push the wheel out of the wheel arch 1/4", give or take.
The further you move that wheel out the more stress you put on the wheel bearings, you also alter the suspension geometry and how it transfers forces to the wheel, slightly.
Most rally setups drop offset to bring the wheel in for less bearing stress and more response in toward the suspension assembly. They actually designed the cars with such high positive offset to allow for bigger wheel bearings so it only helps with all the abuse.
I'd keep as close to stock offset as possible depending on rim width, maybe a bit more positive if you're worried about clearance on your perch. 45-48mm, say, with a 7" wheel.
Personally I think the wheels sit inside the wheel wells a bit too much, but that's just for aerodynamics, +/-1/4" or 5-7mm would really change the stance nicely, in my opinion.
Have you picked out wheels? I'm kind of stuck on getting something hub centric but those are far and few between in 16" and I want to reduce rotational mass a bit for performance on my hybrid build since my G015 aren't much heavier than stock. Those ko2 are 8lb heavier per corner so some nice Method wheels at 19lb a piece, or 6 +lbs under stock, would help offset your wheel weight and bring you back closer to stock!
I'm really leaning toward method even though they don't come in black, Subaru has been using them on their rally cars.
Good luck!
