god marco how manytimes have we dont this discussion over the year now pal

i have used, std viscous, uprated viscous, ATB, and plated all in competition, on tarmac and the problems found were as follows

std viscous - might as well have a std diff unit, not worth bothering with as any decent amount of power will over come the viscous unit when the fluid warms .

uprated viscous (450nm) great to launch with put the power down really well, until the unit warms up - which was really fast being so tight, the unit will lock so you turn for a fast corner and as the diff is locked you go straight on - bad manouver

the ATB (or quaife etc) ok as long as both wheels are on the ground, with equal grip - as soon as one lifts or hits some loose (ie full corner speed) then the drive is given to the least ressistance - i.e the wheel with the least load

the plated (gripper/r+d/salisbury/x-trac) these are the shit for power and control, will never lose drive, can be a bit noisey at times but the differance in power handling/control of the car is far superior

but hey .................................................. .what do i know