I put Dunlop Direzza Star Specs on my 65 Fastback (Paladin) and I am really impressed with them. I also dropped the coil overs down 3/4 inch in the rear and 1/4 inch in front and changed the rear camber on the IRS from -4 to -2 degrees (needed for tire clearance, but i changed from a 275/40/18 to a 265/35/18).
Its like a whole new car. The handling and cornering are unreal. I have gotta run the cones to get some hard numbers, but on some twisty back roads I have not found the limits yet. The subjective handling is soooo much better. I get so much more feedback, it gives you more confidence to drive teh car harder! hard to explain, but its worlds different. Really pleased.
I also switched to borla xs mufflers from hooker maxflows and now I can have a conversation at a steady 2,200 rpm. Full throttle is still get-arrested-loud, but at least I can hear my stereo at idle!