I've not used the Wavetrac, but have had W212 E63's with the factory AMG Locking Diff (a "proper" LSD), a Quaife ATB and a standard open diff.
For absolute best traction off the line the AMG Locking Diff was the best, but in low speed turns you could feel the inside wheel "pushing", with a definite "stick/slip" effect. Near the limit (and I'm no driving god) I also found it liable to snap changes in traction that could be quite demanding.
On the road, the Quaife gave a better overall feel. Yes, it lost a minuscule fraction to the AMG Locking Diff off the line, but in all other respects was its equal, or even better with respect to low speed round town driveability, and it was much more progressive near the limit.
I understand the working principle of the Wavetrac diff and the benefit it is designed to provide. However one penalty has been described by
@Steve84N, above, that sounds awfully like the low speed effects with the AMG diff. On a track, on a car with electronic driver aids switched off, I can see that it could give an advantage over the Quaife ATB when a wheel unloads. However, on the road an E63's ESP will intervene to brake a wheel that's unloaded, so I'm not convinced that the perceived deficiency of the Quaife (it cannot bias torque if the "light" side has zero torque load on it) actually matters.
All these diff's are a massive improvement over the standard open diff, so to an extent which is best depends upon niceties of driving feel, and the depth of your wallet. I'd love to drive the same E63 back-to-back with the Quaife and Wavetrac diff's to see if the latter has any real world benefit, but I'm suspicious that in practice on a road-going E63 the Wavetrac won't demonstrate worthwhile superiority.
