I really wanted to vote for teh goose!
But, being a sensible nerd, I voted for the BMC kit. My understanding of the matter (from what I have read on this very website) is that the airbox is located bang on top of the engine, and so if you change the standard airbox for something like a K&N 57i induction kit you would actually end up
losing power! Obviously on a GTi this would be quite a concern, on a 1.4 I'm not sure if the prospective power loss would be as noticeable...
With a good cold air feed any of the kits you've seen will do the job, make that smashing induction noise when you're on the throttle and probably release a couple of extra ponies to boot. The reason why I voted for the BMC is that it has a carbon heat shield so is much more resitant to the heat being given off by the engine
Halfrauds do a copy of the BMC under the Ripspeed brand, might do the job for you on the cheap? Its about half the cost of the BMC!
There you go! The extent of my knowledge! I will be buying and fitting a BMC CDA induction kit myself later on this year
