I bought them (think I was the first on this forum). Check out my other thread for a review and video.
Quality is excellent. T304 SS, 200 cell metallic core, and includes right angle anti-foulers. No CEL and I've had them for about 350 miles so far. They open up the sound of the Stillen CBE really nicely. There is a touch of rasp added only under WOT around the 4-5k RPM range. The VQ37 off-throttle hiss is also accentuated by these HFCs but I think this is a quality of any HFC on our cars. Overall, I'm very happy with the ERZ cats...I'd buy them again in a heartbeat.
ERZ Performance High Flow Cats, Install and Review Thread