Gains to be had from cone filter on turbo cars?

[Michael Gough]

Hello,
A few days ago I was looking at the TAP website (tap1.com) and noticed for
250 bucks they have a cone filter conversion box for 5kt cars. I thought
(and still do) that this is an outrageous price. So I was thinking of
building my own box to use a cone filter with. Today at the junkyard, wile I
was looking for a better intercooler, I found something almost like that TAP
piece. It bolts onto the bottom of the fuel dist/ flow meter and there is a
spout that I can hook a cone filter to. So what power gains are typical by
using a cone filter? I am going to use it regardless but I'd like to know
what kind of power is possible to pick up.
Thanks,
Mike
PS the piece I got for $5 to make a cone filter work is a factory Audi
part......