i use a Wavetrac in my 01E custom gearbox, and i like it.
Wavetrac front diff, welded center (Torsen) diff, and locked rear; its a Quattro drag car.
i got the custom dog engagement straight cut gearset from Scott @ Advanced, and i love it!
and FWIW, this car runs low 9 seconds and 167 mph traps. recent dyno with tires spinning on the rollers, it put down 847 AWHP and 611 ft/lb with peak boost at 47.42 psi. its a 4 cyl and i drive it like a rental when i get to race!