I swapped a few different cars from auto to manual ,(depended apon what was available at the junkyard) and from what i noticed that every time i switched it to stick is seemed faster to me,the probe i switched to stick was a lot faster,my 80 capri had 6 motors in it and it was always faster with a stick,I alternated between a 4 speed and a c4, mustangs are not to bad to switch between the 2 but you should find a donor car or else you will be spending more time at the junkyard getting more missing parts.in the probes case I actually got the whole car from the junkyard for 300 bucks and that conversion was a real pain but worthwile expecially when people tell you it cant be done and you do it and prove them wrong.go stick or go broke!