Same here ... all DAZ stuff is running fine with Poser 8. It's definitive NO problem with V4 or M4 or such, mostly it's a problem of the environment, hardware like memory or graphics card, software like OS or drivers, and the rest (not too small) is a original problem of poser and it's sometimes crude programming.

And as far as the gotten answers from SM techs are in question ...
Hm, that people are a little bit let's say snobbish. They are unwilling to except any problem or error shown with stuff that isn't original SM stuff. So the answer that V4 isn't supported is a big big wish ... look to the usage of SM figures ... if DAZ figures doesn't work further in Poser than Poser is as dead as can be ...
They have not understood that poser is a program and thats the one side and V4 and such content is the other side. They try it like if M$ would say Word is only working with letters written either by a MS-clerk or in a MS-building or such and therefor never report us a error if it happen with otherwise done letters ...
That's a poor silly behavior and I'm long enough with IT business to have seen more companies with this attitude vanish than been founded ...