[chumbucket]

I'm pretty certain your controls from the '96 will work on the newer motor.
From a personal standpoint, I think it's a matter of preference. Do you want speed or fuel economy? There were lots of problems with the Ficht motors. This particular motor you're looking at may have had the updates done. I think you'd need a qualified mechanic or dealer to check that out for you. The 140 Four stroke motor (which is a Suzuki with Johnson/Evinrude labels on the cover) has a reputation of being a very reliable/economical motor. We have a couple of site members here with that same combo. Randalmanboater for one. All have mostly nothing but good things to say about them.
From a resale viewpoint, if you're planning on repowering and selling very shortly thereafter, the extra $2000 probably isn't worth it. If you're planning to continue ownership for a while and selling later on, the Four Stroke motor may be a better value. You'll probably get much better fuel economy and a potential buyer later on would most likely view it the same with this economic outlook we are having right now.
If both motors were hypothetically equal good condition and with no issues, I might consider biting the bullet and buying the more expensive motor. Again, that also depends on your forecast for length of ownership.