The numbers are important dude wheel fitment is all about numbers , offsets , widths , tyre sizes etc it all plays a part. Ive fitted a lot of different wheels to a lot of S-bodys so i know where im at not just spouting shit on a Forum.
"I have 7j et 0 195 55 15 on mine, very tight fitment on stock arches."
Of course there tight they have a big arse chunk of tyre on for a 15x7j and low offset but have nothing to do with the sizes that the OP was looking at so why you bothered shotting your 2p in with miss information i don't know ? It doesn't change the fact that your wheels will look like rollerskate wheels being so narrow on a S-body so your missing the point wich is they will look shit of course thats my opinion