Tried both, the ITG is a one piece afair (sponge), the HKS has 3 layers, just swapped mine over, didnt notice any difference but I wasnt expecting any. The HKS is a well made bit of kit for the price. Might post pics later on..
Unless you going to spend the extra and get the Ice box, its really no different. I couldnt notice a difference between the 2 filters. Although Ive read that HKS do make the best filter heads, as the extra layers they have are there for a reason
just ordered a k&n from demon tweeks, £30+vat,(listed as vti but air box is same)
k&n and bmc are best quality imo, and they can be washed and cleaned unlike some others.