yeh I wouldn't use abs piping as an ic pipe in the engine bay gets pretty hot in there. But I don't really see any problem using it I guess. Make sure its thick I guess so it has room to dissipate the heat. you definately don't wanna use pvc because pvc produces a poisonous gas when it burns, and it gets pretty hot in the engine bay. also make sure the piping doesn't bend too quickly.

I think the best thing you could do to keep everything cool is to just get a scoop or vent for you hood.