We've also found that resurfacing the factory rotors doesn't always work. We believe it has something to do with the metal composition of the factory rotors. This is also the case with Ferrari rotors and most (if not all) of the factory dealers will not resurface the rotors because they can't guarantee a quiet car, unless the rotors are replaced.
Also, you need to measure the rotors before resurfacing them to see if there really is life in the rotors. A few owners have asked us for advice to get rid of the squeal and when we had them measure the rotors... they were at or under the minimum spec. You would think that the brake shop would check this, but it seems that they don't always.
If you do resurface the rotors, it seems that turning them on the brake lathe at the slowest possible speed is your best chance for success.
During assembly of the rotor / caliper / pads be sure to clean and properly install all of the hardware and use a good anti-squeal compound on the brake pad backing. Our Pads also have an additional bit of material that helps absorb vibration and reduce noise.
You also want to be sure not to get anything on the brake rotors themselves (i.e. grease, cleaners, etc) unless it is a good quality brake clean product.
Finally, you need to properly brake in pads / rotors. We provide instructions with our pads that detail what seems to work best for our compounds.
We do offer nice rotors for the Maserati that will save you compared to the factory parts. When combined with our Quiet, Low Dust Brake Pads that typically solves the squeal issue.
Best Regards