Get an adjustable LSD, get the center differential bias to 30 front 60 rear, Ive been working on this car for a couple of hours with no suspension tuning yet and it has gotten alot better , the LSD settings Im working with are for the front 5,18,8 and for the rear 7,30,18, my car is at max power and full weight reduction using racing medium tires, hope this helps a little bit as I love this car since i first saw it as a little kid when it first came out.
Also Im using the stock tranny driving the London city course to do my tuning.