I have seen the kits sell for anywhere close to $50-$80 on ebay.Theres a thread here on the site about it just have to do a search.One of the members here bought one and installed himself.

 

A shift kit is not going to fix a burnt 3-4 clutch pack. You can try a shift kit but when it still doesn't work you'll either need to fix it yourself or pick up a used or rebuilt trans.

 

ok,as for the hard reverse,etc. test or replace the tps. if testing,it should do a clean climb from 0.5v to 5 volts.

I doubt shift kit will help,as all it does is modifies the shifts timing in order to dramatically increase the shifts firmness and durability. if its having these issues stock,a kits only going to make it worse as there is a mechanical or electrical problem.