I'd recommend against 5 lug. It was very hard to find a 5x114.3 wheel that is low enough offset for the S12, and it's in a goofy 16" diameter. As you know I went with Rota Grid V's, and there's not many wheels that low of offset... in fact I can't think of a single other wheel that isn't a steel wheel. If you have S13 suspension you might get more clearance in the front, and then maybe you can deal with a higher offset wheel. I used to think rears have a lot more room but at the ride height I'm at, I had to roll the crap out of the fenders and I still seem to be rubbing tire. The fenders are rolled a lot more than I would want to do on a street car. My effective offsets (because I have spacers front and rear) are +10 front, +15 rear. Still rubbing the outer fender in the rear, but without the 5mm spacer I'd rub the inner wheel well.
4 Lug wheel choices seem much better these days compared to 10-15 years ago.