Can someone please tell me what is the difference between the M-17 staghound and the M-17 E1staghound? Is there really a big difference?

Jody, you have the designations wrong. It is T-17 and T-17E1, and the latter one is the Staghound. "T" series vehicles were prototypes during the WW2 time frame; the T6 was the prototype M4A1 Sherman for example. Now, about your specific question: both vehicles were built to a specification laid down jointly by the British and the US for a heavy armored car, based on experience in North Africa. They were built by different firms; and the T17 was a six-wheeler and the T17E1 a four wheeler. I think the two might have used the same turret assembly.
The US passed on ordering the Staghound, and so it was never really standardized. It eventually got the M6 designation but nobody ever used it. All Staghounds were produced under contracts designating them T17E1 and went to Commonwealth operators. The T17 itself was built--about 250. But the turret and main armament were removed and they were uased for base security duties. None left the US, AFAIK.
Greg

Thank you very much for the info. You where a big help.

Here is some info on the T17-Deerhound on WarWheels.Net

http://www.warwheels.net/T17ArmoredCarINDEX.html