And here's the last message displayed on my screen:sudo /Developer/Library/uninstall-devtools -mode=all
BUT, don't expect the same for XCode 4.3 and above. Things're getting simpler now:IMPORTANT: If you are going to install a previous version ofthe Developer Tools, be sure to restart the machine after in-stalling.
sudo rm /Applications/Xcode.app
Good luck, my friend!