I find it a MUST to have a boost gauge when tuning a Turbo Diesel. The vacuum part of the gauge is wasted space on a diesel, the is no measurable amount (By a cheapo auto store style standards) of vacuum present to make use of it. I believe sunpro makes a plain 0-15PSI gauge. This would be all you need since our engines cant stand more than 13psi without an intercooler.