I have only owned cars with timing belts and would replace the belt/ water pump at around 70000 miles. My spyder has 110k on it and I am wondering about the lifespan of these tming chains. Is this an interference motor? And if so should I replace the chain or just the guides. One more question: is the water pump belt driven or does it run off the TC? I wuld greatly appreciate any knowledge on this issue. thanks.