toggle compositing

[Naegling23]

I've been running kde3 with compiz, and will be upgrading shortly to 8.10 which uses kde4, and therefore, will not need to run compiz anymore for all my desktop shinyness. To maximize my system resources, I have created launch scripts for my games to shut compiz off, then back on when the game exits (this way its seemless):
--kwin replace
./launchgame
--compiz replace

so, now that I'm going to be using kde4, how do I toggle compositing features from the command line so I can edit my launch scripts?