Good quality.  It would help if the sales blurb gave the dimensions of the door opening required.  Trimming a hollow door is not advisable.  

Easy to fit in principle but it needs a sufficiently large gap to accommodate the width of the top track and still leave a gap of maybe 5mm behind for the opening door to swing clear.  Doorstops often preclude this, and if necessary have to be removed.  The instructions also assume the door opening is perfectly square and plumb.  In your  dreams.  Find someone who has installed such a door before if you are new to it.  Not at all hard with experience but not good as a learning curve.