I have the Helix and I love it.
The only problem is that the heat shield is removed so if you stick your hand at the bottom of the shaft after driving hard for like 10 minutes you'll feel some heat coming out of the boot cover.
That said I would install it again in a heartbeat as nothing beats the short throws.
I never even *considered* installing both short shift kits.....Would make for a rather expensive
mod - however, the idea sounds very tantalizing...Too bad I can't do it since I have an '04.
Have Alta, promini, B&M etc. come out with '04 short shift kits yet?