I have alcantara on my s4 seats and they are holding up well after 10 years. If my next car is another Audi, instead of a m3, I would definitely look to get alcantara again.
I use a fabric shaver (like you'd use on old sweaters) and they look next to new. Mine typically stay clean, but any stains can be removed with a magic eraser if need be.
I'd say if its a wear area to go with the higher quality stuff, but for your project, what you have would be fine...unless you plan on sitting on the headliner somehow.