I was got the HS CAI and saw on the website that you needed a smaller battery. I was wondering how small of a battery. IF you could tell me the sizes and who makes the batt. also will a smaller battery will i get less power to my amps and subs. If i could i would like to move the battery tray and battery up more to the front. but if i can't do it it doesn't matterl.

a smaller battery wouldent give less power to your subs, you alternater would just have to work more often to keep the battery charged, also u may not be able to listen to your system for long periods of time with the car not running.

LIES ! LIES ! LIES ! you dont actually need a smaller battery for a HS CAI cos i went out a bought the biggest battery i could, as i kept flattening mine cos of the sound system. Theres enough room to install the CAI round the side of the battery. Have a look in the 'AEM BPV on a HS CAI' thread in this section, theres a pic of it.