Depends what size of tires you want to run.
I'm starting with the spacers, and then moving into the box tubing, as I have little time to do all the work that is required. I want to run 30" or even 31" tires, so I will have to go to it with the box tubing if I want to do that. A simple coil spring spacer of 2" isn't going to be enough I've been told... But there are much more experienced people about these kind of things! Hope what I've had to say has been informative!
steveo