Well here's the results:
Normal airbox:
BHP = 256
LBFT torque = 266
MAF = 191
Smoothed Airbox:
BHP = 258
LBFT torque = 273
MAF = 191
Boost was at 22psi and as you can see from the following graph the actual boost with the smoothed airbox holds a lot longer than with the normal airbox.
It was definitely worth the hard work with the following increases:
2 BHP
7 Torques
Smoother and prolonged boost delivery
I've also got a load of sound like an asmatic old man and I can hear the DV a lot more now.
If anyone wants to have a crack at it but doesn't want to attack their own airbox my standard airbox is now for sale. PM me if your interested.