swapped out a t5 for a t5z tranny.difference is first gear is a 2.95 instead of 3.35.much better,less revs more torque.also 5th gear was swapped for a .73 instead of the .63.much better,feels more useful even around town.better on the hiway too.i run 3.89 gears out back.
t5z was original equipment on i belive the 93 mustang cobra.but dont quote me on that.but ford racing sells them new. you can check there specs there.i bought mine from modern driveline based in idaho.reason being i wanted the .73 fifth gear ;instead of the .63 gear. they are good guys.tell them john in vancouver referred you.
eljimbo, they are externally the same as any other t5 but with a steel collar instead of alluminum and a few morebetter pieces inside to handle the punishment a normal t5 couldnt handle.