That's the thing man its so hard to tell. There is most definitely 100% a metal on metal rattle that's occurring and I can reproduce the issue. I originally thought it was something broken causing it to begin with but wasnt able to tell distinct metal on metal until now. I just had it installed a week or two ago at this point and don't remember any rattles on the mufflers when I had them off the car & I did move them around quite a bit as I spent some time polishing them up prior to installation around the house.

There is 100% metal on metal however there is also some really high pitched rasp but it might be the metal on metal causing vibrations in the exhaust under high load. I can go outside and rev her up at idle and it actually sounds pretty clean and decent. As soon as I put it in drive and hit the same rpm range the sound is a high pitched rasp. Its hard to tell between the high pitched raps and pure metal on metal because the engine/intake is so loud with the intake/plenium spacer. Once you put load on the motor there is a distinct engine loud vs exhaust loud. The fact i do hear metal on metal from the rear of the car means something is definitely loose or broken inside the exhaust though.

I can blip the throttle at 10% between 1-2k rpms and hear a distinct metal on metal. It sounds like a bolt is being bounced around a metal can. I will try and drop the muffler section this weekend and take a look. Might even try and make a quick video to post up. I know some rasp is normal but this sounds like a weedwacker/farting throughout most of the rpm range. I have a 2L honda that sounds 1000x better than this with a fraction of the $ in exhaust. Different animals for sure but im telling you if you heard it there is no way HKS would be in business if every car came close to sounding like mine at the moment.