The Jammin RTR is a particularly bad one to upgrade because it has a different chassis than the Pro kit. To do a full conversion, you will need:

CNC Chassis, CNC front/rear shock towers, CNC chassis braces, CNC z-brace, graphite upper plate, graphite radio tray, graphite diff plate, center and rear universals, CNC steering knuckles, CNC front upper/lower block (a or b), CNC rear tow in plate, lowered engine mount, CNC radio tray posts, CNC wing posts. I am not sure but I also think the shocks are upgraded as well.

Just did the math, using Nitrohouse's parts list, the parts come to 534.42 plus shipping.