I'm driving a similar truck. I'd start with a line kit and a new lift pump. I too used vulcan performance for this stuff. If you want to do a box or programmer, the only one that removes the rate limiter is the smarty and that and the extra rpms make it a lot quicker to blast through the lower gears on the six speed. The gears are only spaced 500 rpms apart in the lower gears so quick is good. Stock was horrible with power cutting back at 2700 rpms, smarty makes it pull hard past redline.
Lots of other good options out there too, just my $.02
Lots of other good options out there too, just my $.02