Hi,
If your question is if you can establish the Site-to-Site between the ISR-G2 and the ASA the answer is yes.
If you want to know the performance numbers, you can check the data sheets for both units.
The ASA is a Security Appliance intended for managing VPNs.
The ISR-G2 is still a router. The on-board VPN acceleration card is to off-load the CPU from the encryption process.
Federico.