Scott talks about the conversion of some of the early P-51's into "high speed reconnaisance aircraft". We had the 111th Recom Squadron in Italy flying them. I had an encounter with them. I got lost on my third mission when we encountered a lot of flak. When I pulled out of the dive and looked around, they were all gone! Then I saw two planes which I thought were coming back to get me.
They were 111th Recon planes. We both looked a lot like Me-109's in the air. One of them cocked up to get a good look at me and I saw the four 20 mm cannons sticking out of the wing, so I put the nose down a bit and gave it full throttle and got the hell out of there. I was so "concerned" that I actually beat the mission home. On the way to the deck, I was going 450 mph indicated. When I leveled out on the deck it sank to 405. When I got on our side of the bombline, I throttled back to the red line and it sank to 350 mph!
This is all written up on my page at   http://www.charlies-web.com/WWII_med/contentsced2.html,   halfway down the page.