the shift lever, short shifter, bushing etc will have almost no effect on actual times. its all feel and personal preference.
there is no ONE 0-60 time. for any car. the same car with the same driver could have a wide range of 0-60 times. you have to take into consideradtion track temp, tire temp, engine temp, air temp. a difference in ambient air temp of 5 degreed will chance your 0-60 time. did you just take a shit? did you eat a large breakfast. how much fuel is in the tank. aaaallllll these things make a difference.