Air Intake Demisions

Whats up yall? I just got a 2000 GTP a couple of months ago and the first thing I did was buy a 9" K&N open cone filter and one of those install kits off of grandprixstore.com, but the car doesn't feel as strong as stock and its not showing that i get full boost anymore. So I think Im getting alot of knock. I don't have the money to buy a 200+ dollar CAI, could someone give me the deminsions for building the Thrasher CAI box. That would be cool. Thanks
Ryan

How many PSI boost are you getting?

I don't have a boost gauge so imnot sure the exact amount but on the stock boost gauge the last bar does not show up or it flickers on and off whereas before it would go straight to full boost and stay there.