Silhouette actually sells some parts, including the print-head, on their website.
Just a heads up though, Silhouette is going to release a new version of the Alta, the "Alta Plus", in September, and one of the additions is a part cooling fan. Other than that, and a housing color change, the printer appears to be completely identical to this one, so it may be possible to install new parts on the old printer. The article I read did mention something about the print head being easier to change, so maybe they will offer different nozzle sizes as well?
Do you mind measuring the acrylic build