How good of an idea is to use wheel spacers for the rear. I was thinking about getting a 1" spacers.
+1^You brought up an old post, i'll try to help out. You should never run a very large spacer unless you have extended lugs at least. I ran spacers my 2013 WRX. On my WRX I ran 20mm spacers, which is about .78. I was going to run them on my 99 GT, but I bought new wheels which were 18x10.5 in the rear and I ran an IRS in the rear with lowered springs, so I fit the gap perfectly, if I ran a spacer I would rub the tire. The front were 18x9.5s. Even on stock wheels I wouldn't run anything too large as maybe 20mm which is .78 or 1/4" which is obviously .75 since you don't want to leave your stock lug nuts too little room to tighten down the wheel, that could lead to a dangerous situation. There are many factors at play here, even if you got extended lugs and spacers, now you have to roll the fender if you got too large of a spacer and you have to consider how much pressure are you putting on that one area as it wasn't designed for that. A small spacer is acceptable, a large one, I don't think plays into the correct geometry.