I have a pipercross viper and a drop in filter! At the
mo im using the drop in filter!
The pipercross or any of the kits available with a cold air feed definately give some slight power gains over the cone style induction kits!
The stock air intake with aftermarket filter isnt bad tho as it still has a feed from the front of the engine!
Basically it boils down to how loud you want it to sound!
The Pipercross viper is significantly louder than stock!