DrJones_CMR:Another question is that it says “modified” and lists no statement of the limit of modification allowed. So I could cut one little piece that clips in and should be fine, right?
I've often thought about this WRT fenders - fenders may be modified *for tire clearance.* There IS a limit of modification allowed - you may modify the fenders/fender liners for tire clearance only.
The next step down the torture-path is simple - WHICH tires? The biggest ones you plan on competing on, right? Right. SO....maybe a set of 35" Super Swampers? They're DOT approved.....
Absurd, but I'd not put it past someone. My rain tires are taller (well, used to be taller) than my dry tires, so my fenders looked "overcut" with the 13" wheels on - with the rains, though, they were fine - to me, that's legitimate(my current car had no liners, previous car let me backdate them into the trashcan). No one ever squawked about it, mind you, but it was always in the back of my mind - the fender had obviously been cut more than it had to be - the suspension would bind about 1.5" before the tire hit the fender.
The rains were ~1.25" taller than the drys, though.
The leg I think you've got to stand on is simple - if you cut the fenders, eliminating the mounting points for the outer-edge of the liners, thereby making them hang in space (on top of the tire), you can cut enough of them away that they're not hanging down onto the tire. IMHO, we're not talking about a ton of weight either way, so why risk it? It does make it a bit more complicated, but the rule has to be written for -all- cars, not just yours or mine - IMHO, the allowance is fair, serves it's purpose & lets us do what we want.
.02c!
Iain