Omu Cu Sucu

Hello, is there any difference between subclass and main class? I mean can both reach lvl 80 and have 3rd prof or is it lvl 75 max? Are there standard limitations in place like elves doing dark elven subclasses? Or like having warsmith subclass? Also is skill exchanting working on 25x interlude? I am quite new to the server.

The weapon you receive as a newbie mentions in descrption that you can have a speacial ability. Like for instance the club sais it can have acumen. How is that possible it being a no-grade weapon?