was talking to a chap at autosport about a very trick sadev fwd gearbox on their stand and he was telling me that they now do active diffs for their fwd boxes.....awesome stuff, never tried one, must make a massive difference but like you say, not exactly straightforward to set up and perhaps beyond the amateur (a bit like the price LOL)
A propely set-up active diff is deffo the way to go, as it allows you to have a nice combination of Yaw authority and Yaw damping as required depending what the loading are on the chassis, however, (and especially for a tarmac car) i think it is vital to have both steering angle and lateral / Longitudinal G sensors so you can decide what is actually happening in real time and adjust the pre-loads as required. Even better is to have an asymetric overspeeding epicycilic in the spool so that you can have a positive yaw authority as required!. The big
problem with anything active is that it's only better than a passive item if it is properly tested and set-up. A few years back when lots of clubman drivers started to get there hands on Ex-WRC active transmission cars, most of them actually went slower for a good few years till they learnt
how to set the cars up and which of the multitudinous settings was actually optimum for any given set of conditions.
So for now i am staying passive, and will just put in a very tight setting to start off with, maximising traction at the expense of yaw authority, and only soften it off if the car doesn't turn in well enough.