Hi, I have a pair of hks panel filters for sale for a 370 Z , I also have a pair of the cassette part of the air filter box which I modded to get a nice intake noise as 370's are so quiet but did not want cone type filters under the bonnet, They sound fantastic when using lots of throttle but no difference at all on normal driving which is what I wanted, You just take your old cassette with filters out and fit the modded ones with filters back in, (takes about one minute) I Know people will say they let hot air into the system but the cold air is still being forced into system and very little hot air would get in system and certainly less than the short cone type filters would, ( I never noticed any change in performance at all), Only selling as my nismo is now sold and I can guarantee you will love the sound, £70, If any one wants them, I know hks filters are only around £60 new but my filters only about 700 miles old and the cassette part of filters which I modded are silly money, Thanks Tim