Im wondering what the differances is be tween putting the 3 or 4 speed trans  in a daily driver Samurai is....   

I odviously realize the 4 speed has 1 more gear, but what Im looking for is info on the actual swap..... Whats all involved? is there some thing that makes the 4 speed undesirable for puting in the samurar? Something that makes it harder to put in?
(& yes Ive heard the 3 speed is lower geared, but I dont think Ill need it to be any slower.) Id like to have the rig be able to keep up on the freeway. Ill be running a 1.6 16v  & most likely 31/10.5 tires (since thats what I have.)

The 4-speed is - alledgedly - a giant PITA as it's electronics are merged with the OEM engine.

There are some who have had better success mating the 3-speed (especially a 2wd 3-speed) to a 1.6 8-valve.

going with a 1.3 engine might be a tad more difficult - I am not sure if there is an adapter for that combination.

Another popular swap is the mechanical version of the Asin-Warner 4-speed found in other vehicles.  The first one to come to mind is the Volvo sedan/station wagon. You have to obtain the bellhousing off a TracKick 4-speed auto to make it bolt up properly to the 1.6 block.  It's mechanical and it does not have a transfer case mount on the output so it can be easily adapted to the divorced samurai t-case.

Do a search for 4-speed at Ack's FAQ (see signature below for the link) for detailed information!