[acecob]

I own a DRB, heat has been a killer for me from day one, the reason the vent holes are not open is because the foot wells cover two thirds of where the hole is, I have cut holes in mine where the foot well ends and to be honest I dont think it has made much of a difference. even if the holes were bigger I dont think you would get much cooling from them as most uf the heat escapes from under the car anyway.

By the way in traffic, driving casually I dont get many probs its only when I drive it harder, It seems your prob is getting air through the radiator, like tomcat said a good flowing fan and a shroud could fix your prob