I used Lodexol initially and found it rather thick, (double the viscocity of 75w90 when cold), we lost some power through the trans on the dyno and it also does not stop chatter without additional friction modifier. I now run Fuchs Titan Race SYN 5 which is 75w90 still with 1 bottle of fricton modifier. Your diff looks different to mine, plus mine has an integrated speedo drive....so I would speak to Matt about that.
Chatter is basically cause by friction plate stiction when the plates grip-slip-grip-slip, it can sound pretty bad like a bag of spanners and the trans sounds like it's about to fall apart but it's just something they suffer from. Friction modifier just gives the plates a little more ease to slip, which reduces the effectiveness of the diff slightly but makes driving a lot earier.
Yeah, pulling out of a t-junction and applying power will make the diff lock and you'll find the wheel will want to straighten up and whip out of your hands. It maybe better with PAS but I've never had it and don't want it on a circuit car.......so it maybe just my setup.
I've not noticed any increased tyre wear but the car has only done say 1500miles on this setup and one track session, so it's a bit early to tell. One thing which is quite funny, is the car will drive itself in a straight line under power perfectly. I'm not saying try it on the road but it's funny to take your hands off the wheel and drive and the car stays totally stable
I'll be interested to see how you get on with it, as I have no idea on the pre-loads mine was set to, but all I can tell from driving it is it's pretty high. Steering with no PAS in a carpark is a total pain but I'm used to it now....