I am having some MAJOR problems with Great Lakes Performance Diesel in Lackawanna, NY. I have spent over $50, 000 with this company (the owner is Rick Plauman) to have a custom 800+hp engine built for my Kenworth. I was promised a minimum 1 mpg increase which I haven't seen (and has actually gone down), I have spent almost $10, 000 either fixing things that I was told were fixed or replacing parts that I was told that was replaced with new parts and I have yet to be reimbursed for them (this has been going on for almost 5 months). I have a written warranty and they will not honor it...in fact they want ME to pay for some of this! I am on my 5th turbo since I got the truck back, and they can't tell me what is going wrong. For the money I've spent I was expecting a top quality motor to be built for me with compatible parts.