Very few people are running just a single modded CP3 on a duramax anymore. Even with the mods they don't flow enough fuel to keep the proper rail pressure. I am running a Hellafst twin CP3 kit on my truck at the time and it is performing well. There is kits available from ATS, PPE, and Crank it up Diesel also. Many of them you can get just a kit w/o an extra CP3 if you already have a CP3. There is a good buy on a CP3 pump in the for sale section on here if you may be looking to go this route.