My 2 cents: I ordered a small part and didn't have any problems but felt like I was fleeced on the "shipping and handling" as i recall. I know its a pain to process and send something of low cost so I don't really fault them. It was a turbo oil adapter to AN that i couldn't find anywhere else. I will say that their parts appear to be big $$$ but keep in mind that they are also supposed to be genuine cummins. If that's what you are requiring then maybe the prices are in line. I recently ordered an injection pump from DieselTuff that was big $$ for me so I didn't make my choice lightly. It was shipped super fast from Canada, and I am in South Carolina. He has many parts on his site and I would not hesitate to buy again. Communication was nearly instant and excellent. He is also on this forum so that is a plus. I don't know squat about either one if these businesses or even who owns them. If you check my posts you won't find many, but my recent experience was refreshingly pleasant. If you want and are ok with aftermarket I have used Agkits, which i think is RF Engine, Relliance, etc. Way cheaper than Cummins of course but make your decision based on your tolerance for questionable parts. I have a rebuilt 4bt using aftermarket and it has run great (stock power levels)
Fred