To answer a few questions and address a few concerns.

When done correctly and not completely flattening the lip against the quarter there is no structural compromise in strength of the quarter and you cannot see it from the exterior. I rolled mine with the ratchet, but only rolled the lip to gain about 1/4 inch of clearance on the tire. My car is lowered and with a 295 rear tire when I hit a bump the fender lip would cut the side of the tire. Rolling the lip just a little made all the difference in the world.

Think of it this way, too. Which flexes more a piece of angle iron or a channel? The angle iron is rigin, but does flex more than round tube OR channel. When rolled correctly the lip forms a "U".

Both of my quarters have either been patched or replaced so I didn't do any more damage to the original sheet metal than rust did.

The method I described is a very gentle/slow change to the shape of the fender lip, it's completely different than wedging a baseball bat in between the tire and lip and rolling the car back and forth.....puts much more stress on the quarter and rolls the lip much more significantly....plus the risk ot wrinkling the quarter.