There are limitations if you decide to use a shaker air cleaner. Your choice of distributor becomes limited and you can have clearance issues with the gas pedal linkage. The Shaker on my Bronco is an original '69 351W shaker air-cleaner that has been on the Bronco for a long time (it was on it when I bought it). I'm not sure what issues you'd have with an aftermarket shaker, and I believe some are made of fiberglass. Andrew Norton would be able to answer questions with regard to installing an aftermarket shaker air cleaner.
-Terry