Excellent another "North British" member
The bends on the A9 ? No not yet, we have tended to go up to Inverness and then up to the west (Ullapool way) before - Durness and so on. I understand from the Beeb that they want to upgrade that road to get rid of the bends, but then again the A9 needs a full upgrade to a dual ASAP at least as far as Inverness from Stirling if not further North too. It should be a priority given how many accidents on that road.
Planned to come up north last summer with Junior camping but my mum ended up being terminally ill in England so it didn't happen. Next spring though, definitely - we both need the break and the silence of the wild north.
IMHO for the Toyota you would struggle to improve the torque much. In my Aygo I fitted a couple of CAIs as an experiment and used the SG2 to monitor intake temps - not one mod changed them at all compared to stock which ran the intake over the top of the engine.
If you venture south let us know on PMs
Please update with the mods though, just 'cos I don't think it will work doesn't mean it won't