Stand behind their product.
I ordered the C4 manual , a good manual but didn't cover exactly what I was looking for. I was looking for specific troubleshooting for a 1995 LT-1. Sent a email , not the nicest to be honest. Alan replied , I explained what I was looking for , a low and behold he sent me two more links and I found what I was looking for. He didn't have to do that , especially without asking me for payment , but he did.I am very happy with the service and communication. When I need another manual ,this is where I'm going. Great job Factorymanuals.com.