Mike
I have a PS box with elbow (22) plug, VA box, 275 injectors and a valve body. I am very pleased with this setup. I pull a 14,000lb 5th wheel and love the acceleration when empty. Since I have an auto this is about all that I think the trans can take and still have a good long life. Since you have the 6 speed your options are better since you only have a clutch to worry about.
Doug