April is not far away..can't wait till april???
The car deserves the goodyears. GSD3 is the nearest decendent of the original tires. ZR50>GSC>F1 GS>F1 GSD3
And for the rest of the group, I sent this to the op in a private message and though part of it might be of value. (having put 400,000 miles on 3 tta's over a 15 yr period, I have a lot of empirical study of the situation.)
I have had trouble with tires vibrating at 70 to 80mph on tta's, and the only ones that I have had that didn't vibrate at all were the goodyear gsc's. Moot point here I know. (after the gsc's I used Eagle F1 GS, but they were the worst tires ever! Got rid of them when they were new and lost much money!)
Also, something we have now, that we did not have in the old days was the Hunter Road Force Balancer machine. With that, vibration problems can be cured. It balances the tires while they have the weight of a car on them and then move the tires low spot to the rim high spot. It cancels vibrations. I had a new cadillac with new michelin tires that vibrated and this method cured it. Nothing would have cured that car's trouble and if this machine could do it it can certainly fix the minor trouble the tta's have with vibration.
I have had bad times with Dunlop, Eagle F1GS, Kumho and Hankook.
Good times with
Goodyear GSD, ZR50, and GSC
Cooper, Michelin, Pirelli, continental, and BFG
I was surprised that the coopers ran like michelins for 1/3 the price. Have put coopers on 6 cars and perfect on all. They always were the cheapest available too.