I installed the catless x-pipe today. It was paired with my oem perforated exhaust mod. It was STUPID LOUD. I did a test drive down the street and turned right back into the shop and had them remove it. RASP city. I will not even attempt to add resonators. The resonators will help with the rasp but its too loud for my taste.
With that being said I am selling a nearly new catless xpipe. I used it for a grand total of 3 mins, and then removed. Let me know if you are interested. OP good luck, I was recommended to add some 100 cel or 200 cel cats.