Sort of comparing apples to oranges, as far as 103 having valve seals/guides wearing out and the 104 having head gasket issues either way the head has to be removed to fix. You need to make your decision based on your needs and long term investment, yes the 300ce is a great car and goes harder than the 300e but when it comes time to depart with your beloved car, the 300e will be a lot easier to sell, also the 300e is more refined and finding parts are so much easier and less expensive. I hope this helps you to decide.