I think it depends on what you are starting with. If was I converting an auto car I would think the t56 would be the way to
go. Since, either way you going to buy all the conversion pieces. The fab work isn't that difficult its not like your building a tube chassis.
If you have a 4sp car it would be a harder decision since in the end both costs about the same. I guess it would come down how modified your existing car is. Never understood guys with 600hp stroker engines and subframe connectors worried about cutting their car.