"""""""You still do not answer my question:
2. So any way if it is true sub-d modeler is it possible to import obj of any complexity without modification like retopology and modify them ?""""""

Your definition of a "true" sub-d modeler, is false...

"""""If we are talking about Groboto, yes process are not destructive since it is inside it. But Groboto is not fully featured modeler that allows you to make serious projects. And you have to export obj, to finish it in Sub-D modeler like MODO. """"""

We are talking about Braid art in Modo..... And by the way, You keep refering to "serious projects".. What is that?

""""""Moi opposite is fully featured modeler that allows to make very complex projects. So no need to "Commit" at all... Every time you can change everything inside MOI and then re-export it. I work this way no problems at all...""""""""""

You cannot take your MoI model into Sub-d and go to town, Without further work. You are incorrect.