Duncan,
A mate has launch control on his GT4 with the E6K.
Pretty sure it's just a rev limiter set at 4000rpm etc.
But yeah, he can press the button, hold the acclerator flat to the floor, tacho swings to 4000rpm and sit's there while the boost rises to 7psi in about 2 seconds !!
Launches in that thing are amazing !! He has now broken the diff, gearbox, and engine mounts !!