They are interchangeable, there are two models that i am aware of, the BE1/5
and the BE3/5, and as far as i know there is no significant difference between
them, the BE3 has reverse down to the right, and the earlier BE1 has
it up to the left combined with a release cable operated from the ring on the stick.
They are very much alike under the cover, and at least the final drive and
differential are identical, but there are different ratios availiable, the ratio
is expressed in the number of teeth on both gears on a plate by the final drive
housing.
I put a BE3 from an Mi16 in a GRi, it bolted right up, but i had to
sacrifice the flywheel position sensor, which in my case was just used for
diagnostics. The reverse light switch is different, and also use a different
connector, the linkage looks a bit different, but all it takes is to turn the
end on one link 90 deg., The reverse release cable will be unused.
The other way is about as easy, but you have to swap out the stick to
get one with a reverse release ring and cable.
I put a BE1 from a 205GTi in a Mi16 once, and i remember not getting the
shift stick and cable, so it was quite hard to put in 1:st, i kept getting reverse ;-)
Also: i can't imagine an Mi16 with auto transmission, tell me there was
never such a thing....
/ Tomas
-88 405 GRi