It's not as easy as just replacing the existing OEM sensor.
I believe the OEM signal from the PCM is maxxed out at around 15psi, hence the need
for another sensor. ( As I understand it, the OEM boost gauge reading is not actual manifold pressure, but a calculation
of boost/vacuum based on flow through the MAF sensor....[somebody correct me if I'm wrong here])
So, you're actually installing an additional sensor to monitor real time manifold pressure
and convert it to a signal that can be displayed by the 30 psi boost gauge on the dash panel..
If you've got the skills necessary to replace the gauge(s), certainly installing
an additional sensor would be a walk in the park. The idea of locating it near the booster
vacuum supply/close to the dash panel (maybe even on the back side of the dash panel) seems to make sense as well.
Although I have not seen one of the 30 psi boost gauges from Speed Hut yet, I believe it will simply
plug into the existing GT main dash harness just like the other gauges, but would require only one additional
wire connection directly from the new sensor to the gauge.
I hope some of y'all will post up some pics when you get 'em in hand.
Happy Thanksgiving!
mardyn