depends on the conditions. I have done fraser heaps of times and the level of difficulty always varies. last time i was there the sand was the softest I have seen it but we still got through it all in my lib. i would hate to think what my auto gearbox temps were though as i was riding the shit out of the converter a lot of the time!
ground clearance could be a problem in some sections too. there are some gnarly tree root steps on a few of the trails.
If you do go i recommend taking the ferry to kingfisher bay and giving the mrs a night in the resort

the tracks north of kingfisher on the west coast are almost unused and very nice to drive on through some beautiful scenery. You can then cross over to the east coast and leave via the ferry at inskip.
Its the heavily used tracks that will give you trouble. Maybe take a couple of max tracks or similar with you?
lake wobby, lake mckenzie and eli creek are all must-do's. The fishing off the jetty at kingfisher is excellent too if you like to wet a line.
If you keep the weight down in the car you will probably have little trouble. give it a go i reckon
