I'd vote for boost and intercooler temp...afterall, if you are going to get into that type of mod then you need to look at some engine mods......expect there will be a class for BX's at the tractor pulls!
As far as being water-proof, there is splash membrane for it, but I would never leave my baby out in the rain!!
Now we could go all the way with a PanelView display and wireless 802.11 LAN (which I already have). Then I could upload the Honey-do list to the tractor ... display hours till next lawn-mow... Hours of enjoyment ... Oh and read the Tractor-by-net posts under the shade tree.!
I worked on a mid size Massey with a computer for several months. It had a PTO shaft pickup and electric over hydraulic PTO clutch. The PTO would shut off for no reason - only for the owner and only after several hours of shreading - a long way from town.
Even rigged an oscilloscope to look at the pick up signal. Every thing looked fine for me, and the owner did not want to pay for what it takes to keep this kind of stuff running.
He finally traded it in on a new 4WD JD. Problem solved.
Kidding aside, shyguy you should check to be sure it would hold otherwise. I know with mine, I know real soon as in the engine bogs down. I had to have mine adjusted severly at 50 hours service, the guys could not believe it would not hold at all.
The time to find out it does not is not when you need it most