Please detail your issues fully, as I cannot find a forum post or a support ticket from you that does detail the issues. If you could do this in this thread, and stick to the facts and matter at hand, I'll be able to sort you out.
I use Guru 1.6.12 on Snow Leopard and it works fine. There must be something to do with your particular setup that is causing the grief, but until I know the issues at hand I cannot really help.
Loading times of samples is extremely slow in standalone and in Ableton Live and Cubast 5.5.1 - loading from my FW800 drive
Random graphical glitches - 1. difficulty when clicking on OK or Cancel when loading in a patch (the OK and Cancel buttons flash imtermittently or not even appearing). 2. In standalone/plugin - the colorized pads continually blink or not at all. 3. When triggering a pad there is a long delay when the sample sounds and the pad button lighting up.
General - host crashes or extremely slow to operate when using plugin under version 1.6 or 1.5.
Forgot to add: Slow to initialize standalone version.
slavestate - As you have a support ticket open regarding this issue [ticket #24595], can we stick to that for exchanging information? Having two different people give advice at the same time can cause confusion. I'm sure we'll get you up and running.