The kits are routed differently and so only the later kit will fit your 93. My 89 had the late kit stock. (The elbows and tees will be different counts)
The size difference is quite a bit with those small diameters. I think early is 1/4" and late is 3/8" or maybe 3/16" and 1/4". But in my case the small kit I accidentally ordered made my return system pressurize a tiny bit and my IP ran like crap for a while till I switched them out.
That could have been more from my IP being on the way out and bypassing a lot of fuel, but it was an affect nonetheless. They changed sizes for a reason, right!?