I have a 96 F-body LT1 with a M6. I want to convert to a auto. I was thinking a th350 for price and durability, but I want to keep my speedometer. does anyone make something to do that? or if i go with a 4l60e, what kind of wire harness do I need for the new sensors on the 4l60e? also what do I do with the computer? thanks