Im surprised no one has mentioned it but the sound with the K&N or any after market filter is pretty justifying of the cost. Granted the sound is only on the inside of the truck, it still sounds pretty
You really are trying to live up to your name aren't ya'?
Here I type up all this logic for using K&N filters, and all you add is that they
sound pretty? You really are a funnyman
JUST KIDDING YA' MAN!
Seriously though, they do change the sound a bit. On my Jeep I installed a full K&N FIPK with the cone filter and it gave it a throatier sound - especially at WOT. But also added a bit of a turbo whistle sound - which I don't mind, but some have found annoying.
On both of my IDIs, I can't say. They both had K&N filters in 'em when I got 'em (pleasant surprise) and I have never heard either of them with any other kind of filter so I have nothing to compare to.
There is one thing I don't like about the Banks setup (in addition to the fact that the filter seems to be a propietary piece made for them by K&N that is ONLY available through Banks). With the big, honkin', thick, cast aluminum airbox, my IDI has
NO audible turbo whistle at all - even when boosting at max (about 10 PSI) - and I wish id DID!
I have a turbo, and like you, I love listening to the "mechanical music" coming from under the hood, so I'd like to be able to hear it spool.