I have done some digging 2.6 with 3.0 or 3.2 cams will be similar in power to the 3.0.
But would it be worth transplanting the whole engine to a 3.2?
Depends what you want. How badly do you feel you need more power at the moment? What type of power are you after?
Changing the cams is not going to give you a big increase in torque anywhere in the rev range because, by and large, that's a function of engine capacity. It will probably just move it up the rev range a little so that torque buys you more power. That may not be what you want if towing, for example. :-/
I can testify that a 3.2 certainly has spades of pull from low revs and, having towed at pretty close to the max train weight, with an auto, it really didn't bat an eyelid.
It would be interesting to do a before and after drive of a cam upgrade to get more of a feel for what it does, but if it increases power it can only make the engine more peaky.
Engine change will probably be the better of the 2 options, but much more work and much more money. May need to change auto box(AR25?) and diff (wrong ratio?) as well.
Kevin