Imho the ultimate "sporty car" designed for U.S. roads and attitude was Ferrari's 365. More properly thought of as a 2-seat GT touring car, it was said to be exceedingly comfortable and yet confidence-inspiring right up to its 170+ mph top speed. Very handy indeed for chewing up the miles between the Stuckeys. GM was unable to produce a comparable car until the four-cam Mercury Marine-powered C4s came two decades later.
By which time, of course, the roads were falling apart such that 170 mph blasts had become even less wise than they'd been in 1969.
As all here know, I am a huge fan of the MG T cars, and of them, I think the best advice I've ever heard came from Tom Magliozzi of NPR (or it could have been Ray, his brother). Anyway, Tommy had a TD and his personal rule was never to drive it on any road that was built after the car was made, in 1952.
No interstate travel at all.