glad you enjoying them, they were one of the best things i added to my zed.
Just a note of caution though, have you had an uprev / remap prior to the HFC's if so its likely you need one again asap.
I had an uprev after my exhaust and this made the car run lean, i then added the hfcs which also made the car run lean, combined together the car was running very very lean and it needed the uprev again quick sharpish.
If not dont worry you should be fine, enjoy