How Do You read A Dyno Sheet?

This is the dyno graph from the C50 having the Thunder Mfg airbox that I'm thinking of getting. This is without an aftermarket exhaust. Can anyone explain what it all is please?
This was taken from the Thunder Mfg site.

OK I will try to explain but bear in mind it is now gone 1.30 am and I have been up for 21 hrs and counting so I might get it all arse about face. Oh well. I will be home in another 6 hours & then its the big :sleep:

Stock Run
The dark Blue and light blue lines represent the stock dyno run, with dark blue representing the bhp and the light blue representing the torque.

Aftermarket Run
The lower red line and upper red lines represent the aftermarket dyno run, with lower red line representing the bhp and the higher red line representing the torque.

So when reading it you look at the lower 2 lines together to see the difference in bhp and the top two lines together to see the difference in torque power.

Hope this helps but If you need more help understanding it I will have another go tomorrow night, unless someone else wants to explain first.

Cheers Dave, that explains it. Nice one.