I've had a bit of time over the last couple of days to play with RSTuner. Henk from Fastchip.nl was very helpful with the airbag module issue (I bought the wrong one) and let me pay the difference to get the module I actually needed. That has worked perfectly and I've been able to disable all the missing airbags.
Yesterday I took the car out for the first time since the last round of work I'd done on it. It's had new brakes front and rear, new rear shocks and poly bushes, new anti-rotation links on the front, rear camber shims and new inner tie rods. It feels good, really tight. It was pissing it down yesterday so driving around on semi-slicks was a bit dicey. I found a nice, flat, straight, quiet stretch of B road and ran the RSTuner Performance Analyser. Did two 3rd gear pulls in opposite directions and got some "results".
Both runs were almost identical in both torque and power figures. I'm not sure how accurate this RSTuner Performance Analyser is, but the torque curves really threw me. Almost completely flat. The power figure was 185hp at the wheels which if true, for an engine with 120,000 miles on it, is very, very good.
This morning I applied the Stage1 map using RSTuner. I took the car out again. Similar amount of fuel, same load, similar weather. Went to the exact same stretch of road and did a couple more runs with the Performance Analyser...and, the power is down!
Now the car feels almost identical to drive, maybe even slightly more torquey low down. The flat spot is still intermittently there. Weirdly both yesterday and today (pre and post stage 1 map) the flat spot doesn't seem to happen when the engine is cold and gets worse as the car warms up. It always used to be the other way round.
Anyway, here's some graphs. Blue and Pink is yesterday before the map, red and green is today after the map. Think I might drop Henk an email and see if he has any advice for me.