TCI makes a programmer for the "E" trannies which is a box in the cab with you that you can select the shift points,how hard are the shifts,lock-up,and is a free standing system.It is very expensive through.Stay away from any tranny that was used behind the 4.3 engines.The clutches in the v8 versions are better.
A common update is Trans-Go shift kits,with a 005 boost valve and a vett servo on the 700r's.