The Hurst Mastershift shifter is as good as anything produced back in the 1960’s. They are similar in design to the current Competition Plus 4 speed shifters. They are dependable, but not inexpensive.
http://www.jegs.com/i/Hurst/530/366-...oductId=748673
All other shifters on the market that I’m aware of are relatively worthless. None provide an actual shifter, just a bunch of parts you slap together to simulate the same functions. If you ever drove an old Valiant with a floor shift you’d appreciate how poorly these are designed. These universal kits are prone to missing gears, jamming in neutral, or selecting more than one gear at a time, which can lead to substantial transmission damage. They provide a nice looking stick, but the threads are usually not common to any of the popular knob threads.
http://www.jegs.com/i/Mr.+Gasket/720/7667A/10002/-1
Also, doing a three speed conversion first will require a pretty good side hole on the driver’s side of the floor. If you go to a 5 speed later you’ll have the 3 speed hole to repair, along with cutting the new one.
Unless you really love having a 3 speed on the floor (which I happen to like), I’d wait for the 5 speed, eliminating a bunch of extra cost and having to modify the floor more than once.