My HUD differs by about 1-2mph from my speedometer. Is this common? If so, which is usually more accurate? I haven't tested either yet to determine accuracy. I will be doing that soon using mile markers and GPS.

Doug
'99 Black GTP Coupe

Hello,
Common, yes.
This is always a debate....Mostly goes toward the HUD being more accurate, because of the digital readout coming from the computer, vs. the analog readout coming from the computer. If you find it to be different, let us know.
Later now,
Clint

I would lean 99% towards the HUD because of the fact its wired into your PCM. Its always a mechanical vc electrical debate, and most of the time the electrical one wins. Also if you have upgraded your tires/wheels, ive noticed that my speedo is off, but my HUD is right on.