I have two, does that mean I have a left one and the "right one" ?
603's are similar to the earlier engines as far as fuel injection system goes. The 603 does have a fuel heater and fuel thermostat setup though so that can be a benefit to warm the fuel. Other than that you just have to read up on the possible head issues so when you go to buy a car you know what to look for. Check the head casting # and coolant overflow res for signs of oil in coolant (I don't think I have to tell you that's a bad thing haha). There's several threads so just do some reading and then you will know. The #14 head is the "bad apple" but if the coolant system has been kept up it could be fine. One of mine is a #14 and it has over 250k miles on it and runs great.