I had a k1 and didn't rate it tbh. Was a laggy as a TD04 without the power. Couldn't run a front mount air filter with it because it would just over boost, had to have the stock efi pipe in place to get it stable, which in turn slowed spool even more. I think they were designed to run with stock intake as efi pipe fits perfectly when you remove the rubber bit. It then shat all the seals so I sold it on and never looked back. High boost ct9 was more fun, instant spool and power felt pretty much the same.