Question: I am wondering what is the best aka least expensive way to upgrade to a 5 or 6 speed. any help would be appreciated.Answer:This will be the best and least expensive way… is to upgrade to a NV4500 Transmission.MTGM009N BRAND NEW OE GM NV4500 $1600.00 OUTRIGHT NO CORETCGM008A REBUILT NP205 WITH YOKES $650.00CONVERSION KIT TO ADAPT THE TWO AA50-0217 $600AA712576 CONVERSION BELL KIT $399.00MTC-2.5  2.5 GALLONS OF NV4500 SYNTHETIC OIL FOR TRANS AND T-CASE $75.00Give Scott a call 888-824-2012 he can help you the NV4500 Upgrade.  This transmission is dyno tested before leaving the factory and has a 12 month warranty  Shipping Charges will be added.