4.10s and Steeda pulleys. Next best two items. Cheapest is pulleys, my 4.10s cost 350 for install and the gears were FMS so I think 189. Was years ago.
With the 4.10s, you better have good tires too.
Also a shifter if you did not get one yet, I like the Tri-Ax by Steeda.
Forget the shortys. Worst mod I did. I saw 4 RWHPs for (Headers and Install) $800.
John