Jet chips does in fact make a chip for the m103 300es, but I asked them about it and they couldn't give me any information on how it works or what it does. If you are going to get a chip, I would do some exhaust/intake work first, as the systems in our cars are not very advanced, and with a stock setup the gains would not be very impressive (youd be better off switching to full synthetics as those will give 7-10 more hp according to hotrod magazine) Another choice with chips is upsolute, they will custom program your chip from their local locations, so you can have a say in what gets done...