Michael, a few years back I had the same problem (but not as severe to cut a groove in the tire though...). The tires had a tendency to rub slightly on the front of the wheel openings even after Eric at Dynotech (R.I.P.) replaced the lower control arms with H&R's. There was a hole that had been drilled (like on your car) to install some "relocation brackets" which changed the pinion angle, but after Eric installed adjustable uppers, they weren't needed anymore and he removed them.
But even after doing this, the rubbing problem was still there, so Eric spoke with Paul at H&R about the problem and eventually was able to get some lower bars that were almost 1/2" longer than the stock length (I think from H&R also, but not 100% sure...) which bolt in the original hole and did solve the tire rubbing problem...
Maybe you should give Paul @ H&R a call to ask about this...
Hope this helps!
Claude
P.S: The bolt which the arrow is pointing at in your picture is there to lock the plates in place preventing them to rotate under acceleration...DO NOT remove it!...but if you plan to keep these lower bars, then have the plates welded to the factory brackets for more safety...