I use an Orbital battery in my Tiger-clone, and am very happy with it. It was recommended because (as the name suggests), it will not leak battery acid or fumes, even if you turn it upside down. The reason my mechanic thinks this is important is that you have very little protection from the battery (mine is under a lid right behind the passenger seat). One of my kids sits on this lid when whe rides in the back. Also, I run a hardtop in the winter, so I don't want battery acid fumes in my unventilated cockpit. I understand these are popular in race cars, so you might try the speed shop if they aren't available at the parts house.