At any rate... started upgrading today. Don't have the time nor energy to do it all at one time so just started with the front tweeters.
Removed (without destroying) the OEM tweeters and replaced them with CTD 3/4" silk dome tweeters, which fit right in behind the stock grill. Added a bit of Shoe Goo to keep them in and reassembled.
The improvement is quite noticeable and a nice upgrade.
Looks like replacing the mid-drivers is going to be a bit more bothersome as I will have to make some spacers to hold them.
But now that I know how to remove the door panel, that shouldn't be too hard.
I noticed to today that the manual for my Monsoon system states that there is 4 x 20 watts for hi, 2 x 20 for lo and 2 x 30 (I think) for the subwoofer. Sounds pretty good for such low power.
Of course I will need more!