I can recommend Infinity 6022SI's for both the door and rear locations. The door locations are a straight swap. The stock rears are 4" speakers, and the Infinity speakers are 6 1/2", so you have to trim the sheet metal mounting plates in the rear, but it is worth the effort. These are shallow speakers, and they fit the stock locations well (after the trimming). I have these in both of my VX's, and I really like them. Good base, and adjustable (by 3 db) tweeters. Be sure to put a piece of Dynomat on the metal behind the rear speakers.

Randy