I can tell you through experience, getting hot air out from under the bonnet does help. Those vents should make a difference. With my EFI setup, I had a intake air temp sensor in the engine bay and with a non fluted bonnet, on a 26 degree day, under bonnet temps would be around 40-50C. The moment I attached a fluted bonnet, temps would be around 4-5 degrees above ambient. Of course if I was stationary it would climb slowly but we don't race or drive parked in our driveway...