Are you building a race car? I may have missed what you were up to, so sorry if I missed it, but why do you want to put GTV6 bumpers an Alfetta?Gran Turisimo Body kit GTV6 front bumper.
Is your concearn drag or were you hoping to reduce lift ala "ground effect"? If lift, I doubt skirts will be much help, but have you considered a dam, splitter, belly pan / undertray? If drag, probably all you really need to do is keep air off the front of the tires.Gran Turisimo Body kit GTV6 side skirts (set).
Off the top of my head, I'd say if your car is pretty straight, you can increase the track by at _least_ an inch, maybe two, over stock without having to touch the wheel arches. Also, the wheel arches aren't boxed in, so if you need them flaired, you can probably recontour them just about as far as you please (within reason) with a hammer and dolly.Gran Turisimo Body kit GTV6 wheel arch set.