Umm? Really, people actually gave likes for this comment?
To answer it, by the fact that it LOOKS like a Redbull Car and SOUNDS like a Redbull car, and then kicking the person from the lobby for using it.
This is a completely different issue and nothing at all to do with hacked cars in lobbies.
Actually, that's not a legitimate complaint, at least not one unique / specific to hybriding, either. How do you know whether that Red Bull car has been power limited or not? How do you know that GT300 car doesn't have a different turbo fitted? Surely choosing your car according to the outward appearance of a would-be competitor's car is unreliable, unless it's supposed to be a stock car room.
In that latter case, though, you ought to set the "stock car only" flag in the room options - this might need confirming, but surely that blocks hybrids from joining, too (certain hp hacks might slip through, but those will be obvious one way or the other).
My advice: race to the regs, that's what everyone else is doing. If someone wants to come in with an under-performing car relative to the regs, they're clearly setting the level of their own race - maybe they want more of a challenge, and you're inadvertently ruining their experience by choosing a slower car. If they appear to have a better car, remember the regs.
At the end of the day, you know what you're racing, and everyone else knows what they're racing, individually. But if there's scope for voluntary and optional "leveling" of the playing field (by choosing a slower car to match someone else's), surely the issue isn't actually one of a car's outright pace, but one of the player's pace in that particular car? That's what Shuffle racing is all about, incidentally.
Failing any of that, communicate with them. They may lie, and that will become apparent in the race. That, again, is not an issue specific to hybriding.