I have the Viper kit on my LC at the moment - dono what the Dia. is - but its bigger than a standard 57i for instance, looks about the same as your jetex ones. Does this sound about right as your saying about them being restrictive inside due to a smaller cone? Mines off a Clio Trophy, so a 2L engine, so its a bit bigger than a normal one.
Coupled with the direct air feed surely this would be better than just an open cone, espec to reduce heat soak?
Or would a Jetex / Neuspeed cover guard be a better option?
Everyday / track use car. Love the Viper on the track, but sucks up so much crap on the road and also rain going straight in, into the engine - room for concern??