I fancy a rear diffuser from HT autos (05 blobeye with jap style rear box) but do these need sealing on the leading front edge? I was thinking it might act like a parachute otherwise, anyone had one of these?

 

I have one, its not sealed at the leading edge, you get a bracket with the diffuser to fasten it to the car. The one that came with mine went no where near, but I altered it to fit and made a second for good measure.

 

OK, thanks.