Depends how much you want to spend. Edge Juice with attitude is definately the best in my opinion. You can make power /smoke adjustment on the fly, and make big power. It most definately has enough power to kill a stock automatic trans. If you are just looking for a kick in the pants, get an edge ez. It will make a noticeable difference, the are fairly inexpensive, easy to install (plug in), and won't hurt durability to bad.