First of all I love the performance upgrade and the sound this gives my bike. I installed with a high flow air filter and custom ECU tune for track riding and WOW what a difference. I was actually running stock exhaust with an ECU tuned for track riding for a couple of months, which gave me more power delivered in a more linear and smooth application. Then I installed the Yosh 3/4 exhaust and got to the real potential of my bike. It opened up the power band in lower rev’s and really hits hard all the way to WOT. My bike lost over 10 lbs. , too! The pipe looks great and is high quality all around. No 5 stars because for my 2020 R1 the left mid-pipe doesn’t fit perfectly. It doesn’t fully seat on the header pipe when you go to bolt the hanger on. Installation differs slightly than shown in STG video in that on my bike you keep OEM gaskets from header pipes to mid-pipes. These are impossible to remove without damaging them (they are woven thin metal with a lead coating one side). If I had known this before installation I would have bought a new set, but made them work; will change soon.