Good condition $200 - Will need to purchase your own battery posts.

The information as taken directly from AMS website:

The AMS EVO VII/VIII/IX Small Battery Kit replaces your heavy factory battery with a lightweight race battery. This kit significantly reduces weight and frees up space for our free flowing upper intercooler pipe. Our high quality components guarantee long life and the battery itself will have no trouble starting your vehicle in harsh conditions. The tray included is TIG welded by hand using high grade aluminum and the battery is topped off with a CNC'd AMS tie down plate. All factory mounting points are used making installation simple. While it can be used in cars with mild stereo upgrades it’s not ideal for high output stereo systems.

Features
Effortless install uses factory mounting points
Entire kit weighs 15lbs. lowering overall weight
High quality, long life, car starts every time
Custom AMS battery tie down plate
Kit Includes
AMS small battery
Aluminum AMS battery tie down plate
Zinc plated tie down hooks to prevent rusting over time
Nylon washers to keep the hardware from scratching the anodized tie down plate
Durable non slip battery pad to keep the battery in place and protected
Wing nuts for an easy install and removal
Adjustable for use with almost all small batteries
Specifications
680 cranking amps
Short circuit current over 1800A
25 minute reserve capacity with 25amp load
Length 7 1/16"
Width 2 15/16"
Height 7 3/16"
Weight 14.6 lbs
Applications
Mitsubishi Evolution 7, 8, 9
GSR, MR, RS and SE