Rear suspension recommendations?

For carving up the road, the thickest sway bars should be found and used along with agressive shocks. The KYB's are a nice upgrade, but I don't think they'll cut the mustard for the description you gave. Wide tires on all 4 corners of course.

However, this is all the things you don't want for a great launch except wide rear tires.

Shorter shackles like mentioned would be good to use. I understand tire clearance is a problem with that move. Mini tubs?