I used to have that exact boost guage, it's pretty nice. One of my favorite features was the peak hold. The number display showed the peak value, but the "analog" part of the guage was still in real-time.
My biggest issue is that it reads in kg/cm. It's very close to BAR, but it was hard trying to do the conversions in my head. Still a very nice piece of equipment.
On a side note, Defi also makes a HUD speedo/tach.