it is a bit, but once youve got your head round how to set it up.
only problem, noted on a pug 306 dt, is they dont sound to good. but maybe down to the turbo and psi pressures it makes.
a dv on a derv is for show and will serve no purpose, so to be fair if you want it for the sound then do it, but itll serve no function as the diesel dosnt have throttle plates to cause a backpressure to the turbo.
not only that as it is a diesel you may loose a bit of in between gear power. as your relising pressure that the engine actually uses to keep the engine spinning between fast gear changes