Concorde (not sure if this is in the right place)

[Thud]

Hey guys, I downloaded this Concorde
http://www.simviation.com/simviation/?I ... &mark=5521
And I deleted it after a couple flights. The reason(s) being
1 It says Overspeed at 400kts
2 Almost impossible to keep in the air
The reason of #2 being that while traveling at approx 60,000ft (or any altitude) I need to pull back constantly to keep the nose from diving. I looked at the weight distribution and the CG is WAY over where it should be. If I shift the weight to the back, it doesn't really help. If I put more weight in to make the CG right, it's overweight and just falls out of the sky. Does anybody know why this is? And are the other Concorde downloads like this too?
And if somebody knows of an update to make the overspeed signal at the appropiate speed.
Thanks!