Well, if you keep stock injectors, NEVER bump up the rail pressure with your Smarty or any other stack of any kind, because everyone I have talked to say the stock tips are prone to cracking with added rail pressure.
IMHO, get aftermarket nozzles or complete injectors and go from there. If you are not going for big power, the other posters suggestion of the DDP50's is a great idea IMHO.
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'07 Dualie, 5.9, G56, SB3250 DD, Free Flow Exaust, Silencer Ring & Baffles Gutted, Smarty **To Do List** Guages, AirDog 150, CDP 80+hp Injectors, PhatShaft Turbo, Arson II kit, Amsoil Nanofiber, CoolerTubz Intake, BD Intercooler