4" MAF Ducting and MAF Relocator

[holdenvx38]

hey all,
just put in my custom cai (pipe coming from sidebottom of air box to under the car) noticed a fairly decent increase BEAUTYYY (and you can barley see the thing ), just seeing has anyone made there own ducting to their throttle body from the top of the air box??? if so what did use use?? any increase or a waste of time????
iv had a look at F.I.Ts:
4" MAF Ducting and MAF Relocator
seems good but pretty expensive seeing if anyone has made their own??? or have any instructions??? how much would i be looking at or am i betetr off paying the 120 ?

[GMMAD]

just buy a HSV pipe or similar they come up on ebay all the time