changing back and forth to auto and manual would cause even more problems, if you cannot find a clean car than swap is the only option left(in ur case), my recommendation would be to sell your tranny and buy a complete engine with transmission(carby mira), mate the tranny to ur car and sell the engine, this way you'll be free from the hassle of finding vital parts needed to attach the tranny to ur coure's engine and only major parts u'll have to buy other than that are shifter and meter that came in auto coure.