From about 2005 to 2006 I had a very good and well set up plate R200 3.9 and soon learned that plate diffs are not without their own set of quirks and foibles
In late 2006 I contacted Quaife and they installed and setup an R200 3.9 for me and the difference was chalk and cheese
Plate diffs
Need to be setup for the application.
Require periodic replacement of the clutch plates = cost
Require more specialised fluid = cost
Can get very warm, possibly requiring specialised cooling (depending on app)
Can create significant understeer in very tight low speed situations (button roundabouts)
Can be a little digital (either on or off)
Can be a little noisy (chatter)
ATB’s (Quaife etc)
Fit and forget
No specialised fluids
No additional noise over standard diff (none that I could tell)
No tweaking or additional setups
VERY robust (see later story)
Progressive, feeding torque % depending on traction
No additional cooling required over standard diff
Downside of an ATB, if you lift one wheel (rally stages or very stiff track setups/solid axles) they can get confused and require a rapid throttle lift which can take some getting used too.
In 2006 the Zclub went to Bruntingthorpe for a day’s play on the runway doing some timed telemetry runs for JTuner (I think), on one run I accidentally shifted from 3rd to 2nd at about 105mph, tach hit well over 9K rpm………big bang from the back and I’m thinking valves pistons and Quaife.
Engine checked out probably due to the Kameari chain tensioner a well-built engine and a decent crank damper, but the back end was banging like a bangy thing on acceleration and deceleration
Looked high and low nothing obvious, so I thought it was Quaife internals, phoned Quaife, told them and they politely laughed saying something like “it very unlikely” (paraphrase)
On detailed inspection It turned out to be the solid diff mount had snapped in half
Moral is that they are bomb proof unless badly maintained, badly installed or shockingly abused, when fitted they are almost unobtrusive and don’t appear to display any unpleasant or unnerving characturistics (none that I have noticed)