onlu concern I would have with a DIY is on resale value if you left it on when you sold it. Most people would walk from it.... at least most non truck modding experts will notice brands like K&N, Volant, etc....revolution said:volant CAI or custom & efans. i'd do the custom with efans.
check out these links, you can get whatever you need to make your own. you'll need a 4" elbow to the TB, reducer to the 3" MAF unit, cone filter, 4" tube, clamps, etc., heatshield. you could even do a ram air.
http://www.airflo.com/ - they have more stuff than is listed on the website
http://www.intenseperformance.com/products/cone_filters/cone_filters.html