this is not a plug n play...that legend has never shown proof that it is a 6 speed....so calling BS on that...why?
well, if I remember correctly -
* the Type I/5 spd has a single flywheel setup, the Type II/6 speed has a dual balanced flywheel setup. How would the 6 speed just drop right in? I would imagine that this transmission need be compatible.
* new ECU required [1 of 4]
* reverse lockout wiring would need to be done
Now, if you wanted to experiment to make it work, its one thing, but to seriously enjoy the novelty of it being a 6 speed, you will want the other engine...it does make a difference.
As far as performance goes, to get that acceleration requires both parts of the puzzle. NOW, if you do a COMPLETE swap then you will have the joys of a 6 speed...but be warned, if you do this, make sure that this is the car you want to keep....I am sure LPB will tell you...insurance will disown you in an accident/resale value will be lower since the car has been modified.