Should I step up to a custom Dyno Tune?

[71chevystep4x4]

My trucks been running for almost a year now, and Im always very pleased with how nice she runs since I finished the 5.3L swap. Only now I'm really starting to wonder how much BETTER it can get? It's bone stock, in a 4x4 with the original 4 speed manual tranny, with 33 inch tires. My original goal was just efficiency and reliability, which I have now, but I've been running on the $75 mail order tune from LT1swap.com. So how much will a custom tune improve her from here? Will it really wake her up? because I am pretty limited as long as I have the 4 speed in it, which will be replaced at a later time.