I have a barely used pair of HKS drop in filters. They've been on my car for less than 200 miles before i had to leave the country for work. My car has been sitting there undriven and i just got a new injen intake.
I've also heard mixed reviews about its performance and filtration ability. I, personally, noticed a slight increase in throttle response and sound but that's about it. But I can't say anything about how well it filters because i only drove on them for a couple hundred miles.
I got them for $60 brand new.
Im asking $40 obo, pick up in Los Angeles, will ship at buyers expense.
Here are the pics