many Vortek kits over the years. They've all sagged to some degree. They produce a very nice shot cycle though. I've had 1 v-mach kit and 2 Maccari kits. The v-mach and Maccari kits both improved the shot cycles but still left a slight buzz. Their guides have not been quite as tight as Vortek's kits. All my experimentation has been with R9's and TX's.
I currently have a maccari kit in my R9. Nice shot cycle pushing AA 8.4 at around 880fps. Slight buzz. I've also had Ed make me guides and pistons over the years and I my have him just make me a tighter guide for the Maccari kit at this point.
"Grasshopper" Student of the game.....