Single turbo vs twins has nothing to do with "playing well". All that matters is how much power you're going to make on stock internals, the rods are the weak point above 260-280whp.
Im guessing you are looking at the SDP kit? They will modify the stock downpipe to keep it all emissions intact, you can run the stock tune when it needs to be tested. As for a custom tune to make power you're probably going to need to look north of the border. Check out Great white north diesel or Same day tuning, call them and see if they can help you out.
I have had the twin turbo from SDP on my truck for almost 3 years now and have not drove it as it has been sitting at custom shop that never could get a tune that wouldn't throw the MAP sensor code and put the truck into safe mode. I now have it at the GMC dealership to first install a whole new exhaust system since someone stole the entire exahust system front to back of the truck. I will see after that if the dealership can get the truck to not throw codes before I decide to probably put it all back to stock.
Are you running the stock map sensor? Its only good up to 29-30 psi. You may want to look into the upgraded one from duramax tuner.
We did change out the MAP sensor with one from a 6.6 Duramax that is suppose to work better for over 30psi of boost.
Have you asked Scott from SDP for some input?
I have called several times and left message. I also have emailed him with no replys.
