Help me make a Buy/Sell Decision

[lamborghinifan]

Ok, I'm just at a crossroads with my ute, 2004 BA mk2, dual fuel. 4sp auto.
Love driving it, has most of the bits (bullbar, alloys, ipod, tranny cooler, undertray toolbox, spotties) i want, but as i am considering working for myself and will constantly carry about toolboxes, ladders etc, the 4sp just doesn't cut it when it comes to say slipping a quick right hand turn etc, just needs that extra gear with the weight on board.
until now it's mostly been an empty highway cruiser, i've owned it since nearly new, after my grandfather bought it new, and it has 110k on it. it owes me nothing and i am prepared so spend a few say, $2-5k to get what i want.

my questions:
Is it possible/feasible to slot in a 5sp auto, are they much better?

I drove a 5sp manual today, liked it, but i imagine would not be a feasible conversion. Are these a weaker setup, and how do they go with GAS.

Is is better selling (12-14k) and upgrading to say a bf mk2 manual (14-18k), do they come in a 5sp auto? I still like the ba-f shape and interior.

Also to remember is I have had the LPG conversion done. it has well and truly paid for itself, but it is the mixer setup, so a little sluggish. I would probably convert if I upgraded with an injected system.

any thoughts/experiences appreciated