For clarification: ETA and GP are two separate entities, thus each manufactures their own movements, and does not share them with one another, save for when they need to purchase spring components from Swatch-owned Nivarox (Swatch also owns ETA). Yes, Bvlgari uses movements manufactured by both companies, but that really is inconsequential, since GP cal. 3000-based / GP 220 movements really are incomparable to ETA's 2892 and / or 2824, different kinds of movements, designed for different purposes. It is not true that when "˜companies' modify ETA's movements they barely resemble the original. Alas, the only prominent complications that are / can be regularly added to a 2892 is either a perpetual calendar or a modular chronograph; granted more technically complexities can and have been added, i.e. alarm, but for the most part, other movements are more apt for the task. As well most watch "˜companies' don't modify anything. Only a handful actually have the technical skill to modify movements to the level of complexity you are describing. If modifications were so easy to perform, individual master watch makers such as the members of the AHCI and individual firms such as Renaud et Papi (now part of AP), Dubois-Depraz, and Kelek (now part of Breitling) would be out of a job. These match makers / specialty companies design and create individual complications for watch companies. The two most reworked movements used in wristwatches that I can recall are: 1) IWC "˜Il Destriero Scafusia': based movement Valjoux cal. 7760, modified to include Rattrapante, Tourbillon, Perpetual Calendar, Moon phases, and Minute Repeater. 2) Ulysse Nardin "˜Ludwig Perpetual (and variants)': Lemania cal. 1352, the integrated chronograph is completely removed and the main plate and subsequent bridges utterly reworked to fit the worlds only forward / backwards crown-settable perpetual calendar. Rolex's movements are basic in only that they do not have complications. Rolex's movements were designed for one purpose: to serve mid-to-heavy duty everyday working requirements. Thus, they are simple to fix, made of thick pieces and can take a beating. If I were to compare the Rolex cal. 3135 (as found in a Submariner) with another movement manufactured by another company, I would probably look first towards the ETA 2892. Rolex used to utilize the Zenith El Primero chronograph movement for the Daytona, but now utilizes their own in-house chronograph movement cal. 4130, which oddly is based more on the technical aspects used in the F. Piguet cal. 1185 than those used by Zenith. Rolex's are inheritably designed to be more durable than Patek's, such is their individual design. At the same time, a Submariner looks as good with a tuxedo as a hand wound perpetual calendar Patek can be used for diving, to each watch it's own. Yes, Ebel's repair dept. thinks that they are Patek with what they charge, especially to replace $10 ETA quartz movements. Jon.