5-speed options

I'm considering installing a 5-speed in the Dart which I hope to have here in several weeks. I'm thinking that a 5-speed would be more fun than a 4-speed =)

25+ years under my belt pulling wrenches and fabricating is not a problem so the "kits" offered by vendors are of not much interest (unless the time and cost of chasing & machining used pieces exceeds a kit!)

Options? Pro / cons? T5? TKO 500/600?

Going to be used with a 360 magnum, perhaps with a power adder later on.