I finally installed Snow Leopard this week on my MBP. I had some critical projects going on and couldn’t afford breaking anything.
So the first thing I had to do was to update my Quartz Composer Plugins to support Snow Leopard. There were some issues because QC 4.0 runs in 64bit and my plugins had only been compiled for 32bit. But now they should work. I still need to sort out a few issues (check your console for details), but everything seemed to be working fine when I did some tests. Let me know if you have any problems.
Download here: http://mansteri.com/software/