ZZP's kit is 4 spacers that you could buy at the hardware store for $3. They did have plastic spacers and those could mushroom. I'd buy metal if I were buying just spacers.
Thrasher was bought up years ago and only sells stuff online. Their kit might include a couple extra spacers and I think the springs.
Transgo, They are one of the premier trans parts companies. The shift kit from them has springs, spacers etc. If you wanted to go furhter, you could add some additional spacers, but...... unless your trans has been built up. Likely it's not going to be happy with bang shifts.
Each trans I do work on or own gets the Transgo. TripleEdgePerformance one of the best vendors for a trans, recommends and installs them as well.
