i've got to be honest... after having a look at the VF and Dbilas systems i cant see how they can insist on the VF !?
ok, the filter is open air, which imo isnt better than an enclosed system but the rest of the pipe work which is where any restrictions would be seems about the same.
so... for an upgrade to your mapping they want you to spend £200+ on another induction kit when there is nothing wrong with the one you have !?
no brainer to me !