Want My Front Flushed And My Rear Poked

[simpletool]

15mm spacers would go close enough for you (but 8" won't be really flush - too thin). Make sure they are hubcentric.

If you run more than +25 offset on the front it will scrub if you corner hard. That's why you really want 9.5" rims on the front - wider rims means the edge of the rim will sit out further with the same offset. Then you could run 9.5" +25 on the front and it'll be flush and not much tread scrubbing.

[Taleb Tyres]

if going less than 28mm make sure the wheels have backspace for the protruding length of the existing studs(otherwise the adapter will be resting on your old studs which is not safe!

heres 19x10 front +19 19x10 rear +19 +35mm rear adapters (its an r34 with wider guards though so theres about 15-20mm difference on how much more this fitment will stick out on a gtst)