Pontiac Grand AM 3400 COOLANT QUESTIONS!!

Hey,
I'm the proud owner of a 1999 Pontiac Grand AM GT 3400 SFI and i was
wondering, i changed my dexcool out for the "Yellow Stuff" and i was
wondering if i could put G12 VW coolant in it instead. I would like to
stear clear of dexcool, i've seen how well g12 works on SEVERAL of my
friends VWs and i would like to put it in my GAGT, Would any problems
arise? How often WOULD i have to change it? Will it hurt my engine as
bad as DexCool would like my other cars if it get old, or air gets in
the system?
Thanks in Advance