I just sold my 2007 Cayman S to make room for an M3 Sedan. I liked the CS very much but found it spent too much time parked because I inevitably have a couple of kids with me wherever I go - thus the M3 Sedan. Sounds to me like you really haven't settled on what you want yet. Unless you have so much money that you don't care, trading in and out of these cars will kill you from a depreciation and transaction cost perspective; the market for used Caymen is not good at the moment. Ask yourself what you are really looking to achieve. Do you really need a back seat? If not, the combination of a BMW and Porsche could be great. On the other hand, if you only need one car with a back seat swap the 335 for the M3. Need to have an auto on one of your cars (say, for your wife) then get the M3 with the new gearbox. It all depends on what you are trying to accomplish...