I have never seen any tubular K member other than Maximum Motorsports, or Griggs, so I can't say for sure that the QA-1 is junk, but if I ever bought suspension parts for a Mustang, I'd be calling a shop in San Luis Obispo. I have built more road race Mustangs than most people here, and my cars have won a lot of races. When you're trying to find a welding shop on a Saturday night, the dollar difference won't seem so much. How much is your car worth to you? So why worry about a few hundred bucks.
Cream may rise to the top, but sometimes sh&t floats too.