I recently installed a K & N air filter into my D. Marty Maier just finished his kit to fit on of these into the filter box. Before there wasn't a filter that would fit it correctly. The results......Well, increased performance!! Better acceleration, faster shift points, nicer sound, etc. I was really impressed!! I had put K&N in four of my other cars and didn't notice that much of a change--hardly noticeable. The DMC conversion was very noticeable. Now don't get me wrong.......this isn't going to turn your D into a race car. This is the way I think of it--it's $50 worth of performance increase. How much HP do you expect to get for $50?? Not much--but that little extra kick is worth it, right?? I think so. (the dyno showed 3 HP gain) The filter is about $35 from your local AutoZone (in stock). Marty's stainless steel clips needed to make fit fit securely and properly are another $12. Check it out in the parts section of the Mid-State DeLorean Cub at http://www.midstatedmc.com --Jonathan #000697 Belleville, IL (St. Louis, MO)