My friends and I have been able to accomplish many repairs and upgrades on our 300TD's thanks to your parts and advice. I would say the most useful have been the valve adjustment wrenches and my latest upgrade, the new Bosch pre-glow relay. Since I am running a one-tank WVO only system, the extended glow heat gets it running smoothly within 60 seconds! It was an easy 5 min install that anyone can do and have immediate results. Keep up the great work and super friendly customer service! Marley my dog sez: WVO "smells like chicken!"