Anyone increased backspace via machining rims

I can't get enough clearance by rolling or cutting, since the rubber is maybe 1/8 " proud of the fender lip. So a portapower jack could go inside there and swell the fender line a bit, but that might ruin the lines of the car. So I quess I have to eat my mistake of buying the wrong set up front. Note: just because Wheelsforless has a website and people on the phone to say the combination will fit your car, it may not be true. But I will consult an engineer on the machining option in case it actually works, before trying it. I only need two done, so maybe it's the best cost effective option. But thanks everyone (especially Mr. No) for the advice! Unless I get a clear endorsement from a professional, It's new rims and rubber up front, I guess. Or I could cut all four wells and install fender flares, changing the lines and look of the car, taking a chance that would look fine. Plus filling, smoothing, paint, $$$. Looks like I'm cornered, ha ha.