Moroso Thru-Panel Battery Connector - Firewall penetration
A: I used a product that is made by Moroso for race cars. So far so good.

The Jegs part number is 710-74145.
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1631&prmenbr=361
Also available at other places that don't have such a high (9 USD) handling charge.