1) Is this platform and IOS is capable for enabling IPS Engine?
Yes, it is (3945 with a security IOS image will be able to do it)
2)Is there any extra IPS Services Contract is required (other than the smartnet Coverage) for this router to enable IPS engine and to load new IPS Signature files from Cisco?
No, you are good to go.
I will write a future articule about how to enable this feature on an IOS router so stay tune in my website at http:laguiadelnetworking.com for further information as I will cover all of the details,
Cheers,
Julio Carvajal Segura
Julio Carvajal
Senior Network Security and Core Specialist
CCIE #42930, 2xCCNP, JNCIP-SEC