Outer Limits 4x4 Board

I have a 4.6 with 97 disco injection set up and 4.6 injectors, goes well.
I have a few gearing issues after going away from the problematic 4.11 diff gears, and am looking to re gear with def high range and maxi (mra)
low range.
One solution to gearing is power and torque, so I am just wondering what is out there for the engine,ecu that will also benefit.
Have heard of commodore ecu , and motec, powerchip
and so on, but no real world evidence.
ATM inj,4.6, lt95 1:1 high range, 3.54 diffs,35's looking to go
zf,1.4 def high range, mra 30% low range, 3.54 diffs, 35's

more power
more torque
@ low rpm

IDEAS?

Power is easy.... torque is not.

I guess it depends on how much extra you want and how low you want it...

Supercharger and stroker springs to mind for a bigger bottom end boost, or a cam but other than that I think you'd not be getting any significant gains.