My M25 has 900 hours and runs very well. I have read that some people change or service there fuel injectors at 1000 hours. The cost of taking them to a diesel injector place is about 80 to 90% of buying new nozzles. What are the pros/cons of each or should I just leave it alone and not look for problems? I see no smoke, but the transom on my 1983 Catalina 30 (with the stainless flapper on the exhaust) does get black after use.