I wouldn't say that a 144 without overdrive is a joke. I would come nearer
feeling that way about one that had automatic tranny.
It can be changed fairly easily but you need to get the tranny crossmember
and front driveshaft from the donor car along with the tranny and speedo
cable. It might be fairly expensive depending on where you are and how many
are available.

By getting the parts from the same donor car you insure that the driveshaft
flanges are compatible, as they come in 3 sizes.
Except for the electrical connection (which you can do either simply or in a
complex manner, as you see fit) it is pretty much a bolt-in operation.
You may end up with a speedometer/odometer ratio problem depending on which
differential ratio you have and if the right gears are available for yours.
--
George Downs, Bartlesville, Oklahoma, Central US