If you add a pusher fan you will be pushing engine bay air through the IC and not outside cool air. This plus the aerodynamic effect of the rear deck lid will be completely negated. Why do you think that the engineers in all of the automotive companies decided to pull the outside air in instead of pushing the hot air out through the radiator/IC? I have heard the same argument about the AC condensor in the engine bay that if you wanted a helper fan it should be a pusher. All you have to do is feel the air coming out of the engine compartment in traffic to realise that this is a no brainer. What would make more sense would be to route the IC discharge air out of the engine bay without any restrictions and be discharged over hot componets such as the turbo or manifold area. Where am I going wrong on this?