2) just go to a store that specializes in batteries.. they should know off the top of their head what will fit... and by the looks of it you have lots of room and likely the optima will have a higher cca than your current battery and take up the same amount of space... my car was a pain because there is a washer fluid reservoir mounted overtop of the battery (damn GM)... just look up a store and ask them what will fit... likely you can get an even bigger battery, looks like there is room... in my case my optimas bound to outlast my car..