Hybrid/hacked cars are a good thing in my opinion, they help the GT franchise grow and include more community wanted tuning features, without he hybrid cars made in GT5 you can guarantee we wouldn't have got the wing removal feature in GT6.
Of course there are bad sides to it, people can troll lobbies with insane HP cars, and be deceitful in racing leagues by tuning outside parameter limits. But this can already be done to certain extent without hacking the game anyways.
Also this guys YouTube channel has some nice videos of hybrid cars he created for people that want to see them in action.
https://www.youtube.com/user/jannepanne1983