Proper way to open 'niced' cocoa apps?

[michaelsanford]

I want to permanently modify the nice value of apps like MSN and iChat and Mail when they're loaded, because I have better things for my processor to spend time on, like Bryce, Photoshop, and my servers.

I've read about a few different ways to do that. The one I'm leaning toward is creating an AppleScript that executes a shell command like
nice +1 /Applications/MSN\ Messenger.app/Contents/MacOS/MSN\ Messenger
and launching that instead of the application.

But won't this create a new instance of a shell to run an instance of nice that then loads the application, which would stay open until I close the app, whereby the originating shell would exit?

That seems a little inefficient to me; is there any other way of doing this?

PS I put it here because I specifically want to open non-unix apps, but maybe it should go in Unix/X11 after all...

 

[michaelsanford]

PS another way to do it I heard about is to rename the executable in ./Contents/MacOS/appname to something else, then replace the original name with a shell script that opens the real executable niced.