[73rx313b]

hey guys, i am doing a resto-mod on a 73rx3 and i am putting a 6speed from an 04 rx8 in it. I am trying to figure out if the speed sensor for the speedometer is inside the tranny or picked up from some other location.. i really want to keep my old-school speedo. If anyone out there can answer this, it would help me greatly!!! im hoping that the sensor is one of the 4 wires on the tranny... also are these trannies holding up pretty good? im gonna be running about the same hp as an rx8... thanks in advance for any help