Buy the Banshee or Comet. They are SICK upgraded.
Banshee is my favorite ride, great car. It's fast, maybe not as fast as a couple other Sports cars and not the Super cars, but I think it handles awesome. I've got a Coquette and that free Elegy all modded up, but the Banshee is my mainstay. Only downside is that a good hit to the fender will cause it to rub up against the tire and cause the car to drift a bit, even with 60% Armor on. Still, it rarely happens if you're a decent driver, and the Banshee is too smooth not to drive. Heres a couple pics of my garage. Most of the cars aren't that impressive, and I've since unlocked Chrome for my sports cars which isn't showing in some pics:
The ol' Sabre Turbo and a Gauntlet that's just sitting there to occupy a space for now, going to replace it with a Super car
Heres the Coquette and the 9F Cabrio (Audi), also not a bad vehicle
The Ruiner with crazy exhaust and Ram Air hood, Bati 801 for a mandatory bike, and the Elegy which has since been Chromed out for gaudiness
The one on the right is a basic Sedan, Cheval Fugitive, which I got from a mission. It's supposed to already have bulletproof tires and armor, although I haven't tried it out yet. It's actually really quick for a Sedan, and has awesome handling. I'll probably use the Fugitive for Heists later since it can hold 4 people. The middle car is a Felon that I haven't done anything with, just taking up a spot I think till I find something better. The one on the end is the chrome'd Banshee
Heres a shot of the gaudy chromed Elegy and Banshee