Got the call from the dealer. Injectors were clogged and the different exhaust noise was a cracked muffler. Injectors were cleaned and the muffler was replaced. They say it's good as new now. Hope to pick it up tomorrow.
Good to hear.
As a follow-up, I'd be asking (with low hours) "Why would the injectors clog, if the fuel filter was intact ?".
Rgds, D.