It may strip the way, IDK! Be careful and rinse down the area of your car/paint that you think you may have gotten some SG on. Just use caution though, I don't think it will hurt the paint but, I could be wrong!
I have used SG straight on some road tar that was down the side of my car but, I also rinsed down that area that I had cleaned(keep a bucket of fresh water with you). I also did the job in the shade. Then infact, I proceeded to wash the whole car anyway! I applied(either spray bottle or gallon jug)the SG right on the tar itself and allowed some setup time(few seconds) and the tar wiped right off.
I also believe that SG has dilution instructions on the label and also, I don't think that you'll want to use SG straight as it is concentrated.
As-far-as aluminum wheels, use diluted SG as you can always go stronger!