Oh and I am also trying out one of these, Pipercross Venom:
http://www.thepipercrossshop.co.uk/venom.asp
Pipercross rate it to 450bhp and it is only very lightly oiled. So far so good, does not feel restrictive at all, car pulls the same as with an open cone, doesn't sound as good but with the 3" cold air duct being fed directly from the fog light hole, it's being force-fed nothing but cold air.
I have removed Venom and fitted open cone and got higher airflow..