http://www.mjmautoinnovations.com/sak240sxt65.htm
$15.48 shipped for a pair of 6.5 front speaker adapters...cheaper than the gas money used to run around and look for materials + trial and error fabricating + overall total time invested.....imo
if you do go with 6.5's, double check the depth of the speakers to ensure that they dont get in the way when you roll down the window.
im running speakers 71mm/2.49" deep. i used a 1/4" speaker adapter and two 1/4'' spacers to clear the glass and then shaved off some of the door panel and alil bit of the oem speaker cover