For anyone that has tried the drop-in filter, have you observed or measured any improvement in power and/or fuel efficiency? I'm interested in adding a several hp to my Prius, as it gets a bit winded while trekking up into the mountains on the interstate freeways.
Uh nevermind. Just looked back a few pages and found some replies here: http://priuschat.com/forums/prius-modifications/49301-k-n-airfilter-anyone-done.html ...Thanks.