Bigger Tires
I have the standard 14" wheels and installed Sumitomo HTR 200 tires in the 205/70 14 size after a lot of looking and measuring. While they are not a true high performance tire, they are an order of magnitude better than anything available in the day, and they were around $300 mounted and balanced on the car.
As to how they work, I have just completed the Peak to Peak Rallye which was 1,200 miles around the best roads in Colorado, running with Ferrari's, Porsche Turbos, Corvette ZO6, Aston Martin DB9 and more. As you can imagine, these fellows weren't hanging about and on the twisty bits I was able to keep up albeit with substantially more body roll. The only place I fell behind was on the long upgrades or high speed straights where I would see them disappear. These tires are very predictable, quiet, smooth and have pretty good grip. No interference issues either, despite about 150 pounds of luggage in the trunk and two passengers in a very spirited driving environment. As you can tell, I am pleased with them.
By the way, the coupe got more compliments than almost any of the "Super Cars" except a Porsche GT1 which is "a one of twenty in the world" car.
![Big Grin :D :D](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)