With the new head gaskets that problem doesn't seem to be an issue any more.

I think the 3.4 is a very good engine but the 3.0 aint all that bad either. For what you could spend on the swap you could likely build an really nice 3.0. I have a buddy who is currently testing some mild cams for the 3.0 and initial results are good both milage and powerwise.

I'll be testing the next stage cams on my built 3.0 sometime in the summer. If all goes well I should have more power then the 3.4, better milage then stock and toyota reliability. It will cost me close to if not less then the cost of a 3.4 swap.