Hi Pete,
Not much to gain without a map installed in the PCIII, but I believe the O2 eliminators help with the smoothness (I may yet be proved wrong but it's worth a try for £30 and 30 minutes work).
There are several maps others have had written for various configurations and it could be be worth trying some - just check they are not radically different from stock as the base map is very good anyway. If you can afford it get a custom dual map made for your bike on a dyno.
In terms of power and torque there's not much extra to be had with a PCIII as, like I said above, the stock map is very good, but you can smooth out the snatchiness quite a bit. It'll most likely never be perfect but it can be improved a lot.
Cheers
Rick