I installed a Forced4 CAI over the winter. I already had the Forced4 bypass valve kit and a k&N filter so I PMed Eric and just bought the sheetmetal airbox. There was minor messaging to get the airbox to fit but it pretty much dropped right in. There are instructions on the Forced4 site on retaining the piping to the charcoal cannister, which I did.
I painted the airbox Eastwood underhood black but it would be more scratch resistant if it was powdercoated. I also found some edging to put around the top of the airbox.
I eliminated the flex hose by installing a 3" to 2.75" hump hose between the turbo and bypass valve coupling, and a 3" 45 degree elbow betweem the bypass valve coupling and VAM.
I think this is a relatively cheap upgrade that really helps to uncork the intake. Plus you can really hear the turbo whine!
The only downside, which isn't really a downside, is if you install a CAI you really need a bypass valve. I don't know if the K&N filter actually makes the need for a bypass valve necessary or if you can just hear what is going on better but the sounds/shuddering from the turbo when you suddenly get off the thrrottle under boost are not good with the CAI installed.