Here is a little ditty we used to say:
Never trouble trouble until trouble troubles you.

I would say that the important thing is *not* to select a type of
fabric/carpeting if your cat has shown a preference for that type of
texture.  I have had carpets of various types over the years and have never
had any problems.  Instead, I have always had a supply of scratching posts
with different textures.  I just wrote a fairly lengthy description of how I
have used scratching posts in the thread entitled "Declawing: glad I took
the time."  I do think it could be asking for trouble if you were to
deliberately change to a type of carpeting where the cat has shown an
inclination to scratch on that type of surface.  From your message, I assume
that you haven't had loop-pile carpet in the past but would like one now.
You could buy a small loop pile carpet remnant (maybe even a runner) and lay
it on the floor for a couple of weeks.  Watch to see if there are any signs
that the cat will try to use that surface.  That could be your guide on
whether to progress with a purchase.

MaryL
(take out the litter to reply)

Photos of Duffy and Holly:      >'o'<
http://tinyurl.com/8y54 (Introducing Duffy to Holly)
http://tinyurl.com/8y56 (Duffy and Holly "settle in")