First-gen Mazda Miata is the only low-end car that I know that actually looks reasonably sleek and designed (the second-gen looks like a stupid ordinary car). It's no 911, but it has a nice retro charm.
A well-designed sports car doesn't need lots of power or anything else that should be particularly expensive. It just needs to look good.
There are many answers in this thread about performance, manufacturing tolerances, undermining your high-end brand etc., but none of that should apply here.
I'm asking partly because I think almost all modern cars are hideous, but I also can't afford a 911.