That's a BIG 235 tire... most are rated from 7-8.5", this one is rated up to 9" but still didn't fit right and I have half a mind to contact BFG about it but I doubt they'd do anything. And yes, some rims have thinner lips than others but I can already tell you that an AM 8" wide rim is about 8.8" from lip to lip, a 9" rim is going to be more like 10" and you'll get this look. Rim width is measured without including the rim lip. I just figured mine would stretch a little and pop to the end of the lip like I've seen a lot of them do but nope.
Your options for 8" wide rims on AM are Bullitts and AMRs and that's it. You can get rims from a lot of other places though, just most Mustang setups are 17x9/17x10.5 or 18x9/18x10. I honestly think that a 9" rim up front is too wide on a 94-98. For a 99-04 with the wider fenders they look a lot better.
2000 Mustang GT Steeda #0048
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.