I'm sure you have checked DCM - but have you checked the shock upper ball joints - as Tristanssid has found - they can bind up if over tightened and that will lead to some massively unpleasant and inconsistent handling?
I don't know what else to suggest to you. Things I've done recently as the grip has come up to Stupid levels are as follows
1) Remove TLR rear weight completely - this has the effect of inducing more mid corner push and reduces the over rotation that I actually like but I know others dont. It also improves big jump landings and virtually eliminates the double bounce
2) Add SidePod weights - I'm using Tony's Rudebits which helps calm the car down on high bite especially across adverse camber sections and high speed corners
3) Shorter front link - not sure If I like it shorter (cos I like the rotation) but a shorter front link definitely seems to allow the car to release from the turn earlier and enable you to get on the power earlier (or harder)
I know you've pretty much tried most things DCM - so I'm not trying to teach you to suck eggs - but if any of this helps then all is good.
Lastly, the other thing that I notice with the car (or any 2WD for that matter) is that if the diff is gritty, then it becomes real hard to stay smooth coming out of any corner.
HTH