I just installed mine a few weeks back. I too ordered mine from RNG. It wasn't hard at all except for the left-hand threaded 33mm? nut was a B*TCH to break lose. My 1/2" 18V Milwaukee Impact wouldn't touch it so I had to crank up my 60-gallon compressor and get my Nitrocat 1/2" Impact out. That nut wouldn't break free for the life of me. I was terrified I was doing it wrong, watched the video over and over. Finally, I said the hell with it and just kept the impact on it for 15-20 seconds (which felt like forever) and it finally broke free. After that, it was a breeze! The only other issue was the bolt on the plastic cover closet to the front of the vehicle was kind of a pain to reach even with an extension and swivel.
It did make a noticeable difference after installed! I'm debating on doing the ECU tune via Main Street Cycle as well