Okay, as far as dps-performance. They have horrible customer service, I mean bad. I know 10+ guys who said they will never buy from them again because it was so hard to get ahold of them. I also know guys who bought stuff from them, something was wrong with it, so they tried to return them, but the owner would never answer.
All they do to the injectors is increase the size of the holes on the injector tip. Yes they flow more fuel, but the spray pattern goes to crap. They litterally piss fuel in streams. I know one guy who bought there stage 1's. He put them in, his truck smoked like crazy (kinda a good thing
), got horrible fuel economy, and ran really rough. He pulled them and had them tested, and technically 7 of them failed the spray pattern test they were so bad. He tried to get ahold of dps to return them, never got ahold, and they sit in his garage to this day.
If only 1 or 2 guys had problems with them, I would say go for it, but the fact that I know 10+ guys all with similar problems.....that just leads me to not buy any of their products.
Now as far as elibeson is concerned. If the IP is stock, it might be time to replace. IP life spans are around 100K miles. When you put in the new injectors, they had a higher pop off to when they inject the fuel. With an older pump, it would take longer to build up the pressure, so your truck is now running retarded in timing. Advance the timing on the IP by about a dime's width, that should get your performance back. Or you could get a new IP.