Im quite impressed with my BMC CDA, think ive gained more torque and it pulls better at high revs, but that is in comparison with a completely standard airbox (including the filter)
Air intake is a personal preference unless you relocate the battery and stick a v6 box with an air feed gains will be minimal and without heat shields an open cone would probably have a minimal loss without an air feed.
James it's a shame you didn't live with the standard car for a little longer to better judge the difference the upgrades made. I'm going to wait a couple of months before any tuning partly for that very reason and partly to let the engine run in a bit more. It's good to hear that you've lived with it for so long without any problems etc... Ooh and I prefer going the replacement panel filter route rather than entire induction kit. I've wacked in a piper cross jobby and removed the fun bung for more rumble )
Well when I bought the car it was an ex demo with 5,000 miles on it so it had already been run in. I bought it in Leeds and drove it straight down to K-Tec in Dorset. The drive back up to Aberdeen was fun!