Not long ago, IPVM did a comparison of Axis vs Mobotix advanced motion detection:
Relevant live surveillance footage addressing these issues is not that easy to come by, but here's some imagery showing the effects of audio deterrence:
...and apprehension when deterrence fails:
In case you see this and say, "I want THAT!" you might also want to read a few more manufacturer details:
(software layout) http://ipvm.com/updates/651
proprietary video format or mjpeg, no h.264
What are the dimensions of the area you're looking to cover?
And, I assume 40K is USD?
Chesapeake & Midlantic
The client would be better off with a security guard. It would cost significatly less than 40K, too.
Perimeter fence is 500' x 500' x 500' x 500'. 2 sliding gates (manual). The client doesn't necessarily need detection right at the fence. There are high value areas such as storage sea cans or vehicles that can have coverage instead.
40K USD budget.