By HAI, do you mean you didn't do any more insulation after the Thrasher setup?
By HAI=we used a 99+ f-boot and shove a 00+ mustang K+N filter over the first lip of the F-boot.
The HAI sounds turbo-ish, it whistles at ~3500rpm
. Did the same thing with the G/F gt, I've seen better gains with that than anything else. Even on L67s...
For the $60 (F-boot, and filter) there is no comparison. At that point its just asthetics. It looked descent, but not show quality.Thrasher IS the best looking one IMHO.