The ones for the HHR are for looks only. Cheap thin plastic will not hold up to any downforce. That is why the spoiler is even with the roof line so it doesn't pick up any resistance.

Cosmetic only.

I had a '93 Cavalier that had one of those factory designed air deflectors to try direct air onto the rear window to keep it cleaner.It didn't work.Squared back cars like our wagons are just prone to having dirty rear windows.

:nono:



As I stated in my previous post here, more air flow is needed to be forced down the rear of the vehicle, not less, which is what the "premiere/SS" spoiler would do.