Stay where you are, i had DSM 6 when it was supported on N54L, had some issues with it.
If you want to try nevertheless, try with some other hard disk and usb boot drive and always have a backup!
Now i'm back at DSM 5, perfectly happy with it because everything works as it should be
DSM 6.0 works fine here on N54L - been running the original loader since Jun released the loader.
Haven't had any issues although I am hoping for a 6.1 build compat with it