Aggressor from this list fits most, mainly since middle class is a versatile class, "all rounder" etc. In other words it's the type of performance that benefits from aggressive style of gameplay since you have to play to your opponents weaknesses to have an edge against them. So you can't wait for the part of the track where you can just walk over everything else but you have to skillfully utilise your opponents weakness to gain a lead on all the parts where they can't walk over you.
The problem with this name is that most people won't really go so deep into it and will assume that it means "ram them all" style of car. As with many great ideas, the humanity is the biggest issue.
Roller as mentioned in is essentially a board with a stick and two small wheels which rolls as you push yourself forward. And it reminds me of Rover. All of those things are something that is closer to crappy, unreliable, weak, brittle, slow etc. rather than versatile, reliable, fast, epic etc.
Destroyer is a name for a tank. And I mean a specific car, rather than a class.
Apollo is too specific name, definitely fits more to a certain car that has a theme of sun to it.
Roadster is a convertible. Enough said.
Hybrid... well, that was my proposition and... it's so bad xD The only thing that comes to my mind is a Toyota Prius. Maybe 10-15 years into the future that word will have a better ring to it, but currently... it's just too much of a "fashionable car for celebrities" vibe to it. It describes the class perfectly when seen from a grammatical standpoint but nowadays people are not only bad with grammar, they just think of electrical cars whenever they hear the word "hybrid".
Enforcer sounds like a name of a police car tbh, but given how all the other names are completely way off the mark (apart from Aggressor naturally), this was the natural second choice on the list. That said police cars usually need to be quite versatile, slightly on the heavier side, with decent top speed, acceleration and handling, so that it doesn't matter what car the chased person is using, you can keep up. That of course is theory, and I think we all know how it looks in practice.
I still would opt for the "GT" name that I suggested in the car names thread. The most automotive name that fits the style of the car and describes it perfectly. Even people that aren't interested in cars have a really high chance of getting immediately what sort of a car it will be.