I put a BMC filter in my VZ SV6 and I noticed a bit of a difference, especially at the bottom end with respect to pick up. I also oticed a $30 difference in the servicing costs as they didnt have to replace the air filter......
Put the blue kind one from ebay last week and did notice a slight difference in throttle response have also gone from 14.8 to 13.6 ltrs/100 on the dash and still driving the same mixture of normal and sports mode.
best off going the whole cold air intake system....otherwise pointless i reckon....did it on my ve ss...never go back..but i suppose you wont have to replace it all the time...only wash