USAGE NOTES:

Well, I guess this will always be a work in progress somehow...

Overall everything is fine but I noticed the following:

-Tap to click can be unresponsive for me... weirdly tap to click is less responsive on the dock and top bar whereas it's great on the desktop and in apps... I played with the settings in the pref pane, increasing speed for double-tapping using as a reference the left pane of a finder window for testing... I find the left pane was very unresponsive, trying to click on 'applications' for instance... I reached a compromise also playing with another setting... it's usable and it can be very precise but the tapping somehow feels 'engineered'... there's room for improvement but it works and I can use it now. I always feel it's too responsive when I go back to XP... I feel the difference. I'll buy a mouse anyway...
-Speedstep - maybe not such a good idea after all.. I find during peak usage, when I was installing XP in Virtualbox or using it after, that everything would become jerky every some seconds... I guess while the cpu is being adjusted... maybe I should remove it. Or is it related to something else? Maybe some other kext could help finaly. Otherwise desktop and normal app usage seems fine.

So this is it. Some tweaking remains!