To free up rear on very high side bite surfaces;
Less rear toe (especially useful if done from inboard as also slightly lengthens wheelbase),
Longer wheelbase from rear and/or move centre of mass forward depending on how tight the layout is,
Increase rear oil by 50cst (or 50cst additional over any increase in front oil),
Longer rear link (so rolls slower thus can change direction faster),
Raise inner ball studs BOTH ends of the car (gives the effect of more on power steering which makes the rear feel freer),
Stiffer rear spring (or move lower shock out on rear arm as this gives added benefit of reducing rear droop too),
Reduce overall droop but slightly more reduction in the rear (less roll over all but relatively less in the rear helps rotation),
Take weight out of the car (less force from mass loading the same width tires = less overall grip),
Increase antisquat (less rearward weight transfer under power keeps the front working harder),
Increase rear track width (again best done from inside end as that helps with roll centre placement too),
That is the list of what I do between my normal MM setup and going somewhere like Silverstone which is velcro grippy!!