Hi Mike,
I generally agree and am an Allison fan, but the Merlin P-51's are VERY good, too, as I'm sure you know.
The problems we've had with Mrs. Virginia are all centered in the radiator setup. Steve Hinton finally had enough and they built a new one from scratch. They had initial oil cooler issues, but fixed it after the first flight, and it runs great now. The Allison in it, despite being repeatedly overheated, never gave a problem and still runs great. At lower altitudes, the Allison unit is quite fast and it actually a bit faster than the Merlin unit, but up high there's no comparison since they didn't put the turbo in it ... again, as you already know.
Most P-51's let the pressure out of the hydraulic system when they park and the inner gear doors float downward to the open position. When the engines starts, they come up automatically. In the P-51A, the system retains it's internal pressure and the gear doors stay up, even after years of no moving. They don't go down until gear retraction time.
When I post the pics, I'll throw in pics of "Boise Bee," a P-51C-10-NT. It is here and will fly in the air show. It isn't the P-51B-15 that Drgondog likes so much, but is as close as I am aware we have on hand.