Well in your graph you see the torque drop off at a really crazy speed and drops to a very low amount.
Looking at the graph i posted, Revo stage 1 should drop at a slower rate. In the graph you see it drop to about 280 N*m which is approx 205 Ft-Lbs. Your actually drop below 100 ft-lbs.
TBH i have never seen it drop off like that. The OEM downpipe is a bit restrictive (best to knock out the Pre-cat - give you approx 5bhp extra as well) but no way would it cause such a drop.
Stage 1 needs, nor requires any other mods (ie downpipe) so you should be getting close to my above graph.
Either that guys machine is incorrect or you have a problem with your car. But seems very strange as you made correct Bhp at the correct rev range....