The display itself works great since it's perfectly visible,
even in direct sunlight & it doesn't obstruct your view at all
(it's semi-transparent). I have the display in my line of sight above the left headlight, a few inches off the windshield bottom. At night it automatically dims so it isn't conspicuous. It's actually a lot more stealthy than some of the big ass gauge pods & a-pillar jobs I've seen. I got mine from Bottle at Titan motorsports for $200 ... try searching for "Bottle" at .
www.i-club.com/forums
Only reads in kg/cm^2 (just about the same as bars) but this works out OK for me since my max boost = 14.5 psi = 1 bar
so the readout can be just viewed as fractions of max boost.
So at 1.1 bar = 10% overboost, 0.5 = 50%, etc.
You should know that the other HUD units they sell are all in metric units (like the speedo which is in km/h). On my dashboard by the A-pillar there's plenty of room to put a couple of these HUD units in.
As far as boost gauge versus MAP, my MAP sensor is located somewhere in the intake manifold after the throttle body, whereas my Defi sensor is right off the BOV before the throttle body. I only see this 0.1 bar difference when I really push the car and am going through the gears fast up to redline...
Under normal conditions it agrees with the MAP value
The 0.1 bar difference might be real and just a characteristic of my car's boost spike when the throttle body shuts. I've been meaning to move the Defi sensor to closer where the MAP sensor is though.
Actually I meant to say you can read current & peak boost simultaneously, it's just that the numerical readout only shows one or the other. The display still has an analog readout that always shows the boost level, it's just not a digital readout