I installed 4 gauges on my A-Pillar a few weeks ago.
1 - Tachometer 0-4K RPM
2 - Pyrometer
3 - Manifold Pressure (Boost)
4 - Transmission Temperature

All gauges were Isspro and I purchased them at DIS in Tx. I also ordered 2 A-pillar mounts from DIS (Made by Autometer) so that I could install four gauges. I did some cutting and shaping on the A-Pillar mounts by heating them and forming them a little to fit nicely. I also had a doner vehicle provide me the factory A-Pillar molded plastic cover so incase I screwed something up It wasn't mine anyway.

I mounted the Tach on the lowest hole with the pyro just above it. Next up is the Boost then at top is the trans temp.
All gauges mount pretty easily and the wiring is str8 forward. It is time consuming though. (Of course I had a hoist so working underneath is easier). The tach uses two glued on magnets that are attached to the front balancer on the engine 180 degrees apart from each other. The sensor comes with a useless bracket, so plan on fabricating your own bracket for reading the pulses as the magnets come past. The tach requires you to run two wires from the sensor at the front of the engine to the tach itself. Also, one of those wires needs to be t'd and grounded, this can be done easily under the truck within a few inches of the sensor. The tach also requires a separate ground and a switched 12V that I found at the fuse block under the dash.

Next was the pyro, which was the easiest gauge to install. I pulled the dog house off from inside the van. I purchased the clamp-on Thermal Couple which is approx. $15 from DIS (well worth it). While sitting in the passenger seat I drilled the correct size hole into the turbo down pipe. (I installed the pyro after the turbo). Then I simply inserted the TC into the pipe and clamped it on. No problems, very simple. Then you need to run the wire up into the a-pillar to the gauge.

With the Boost gauge I purchased the Banks (from DIS) boost gauge install kit. It comes with a T-Tap that you splice into the Ford Manifold pressure sensor hose. The instructions are for the truck not the van, so I guessed at which component was the factory sensor, then called the dealer to verify the part number prior to splicing. (It is just above the battery on the passenger side, mounted to the firewall). Then run the tubing into the cab and up to the gauge. Be careful because the tube will kink very easy. I routed my tubing across the top of the engine compartment with the factory wire looms in there holders, then I drilled a small hole in an existing rubber grommet just under the brake booster and slipped the tube through. Also, be careful not to over tighten the ferrel fitting on the tubing... this cost me some time and a ferrel fitting. Although, the kit included an extra ferrel so I guess I am not the only one to have done this.

The transmission temp gauge is pretty simple. Switched power 12V, (found at the fuse block again), and ground. Then the sensor needs to be placed into the transmission. The instructions say you can place the sensor into the trans pan drain plug. The only problem, the instructions are for the SuperDuties and our vans do not have a trans drain plug. (Although I added one but that is another thread). On the side of the transmission just above the shift cable is a plug. You can remove this plug and install the sensor directly into the transmission. It will be completely covered with trans fluid and it threads directly into the hole with out any adapters. Then you attach an 18-gauge wire to the sensor and run it up to the gauge. Do not use any Teflon tape on the sensor. The body of the sensor grounds to the transmission and the tape will cause a poor or no ground situation. It will not leak without the tape, it is a machined thread.

Getting the wiring from the underside of the van to the a-pillar is a challenge. I found a simple way to do it. Run all wiring to the drivers' side of the van, cross over the frame (between the body and frame) near the drivers' door. Remove the drivers door jam cover (just pulls up) and you will find a channel with two rubber grommets. Drill a hole in one of the grommets (I used the forward one) and run the wiring up through the grommet and into the channels, you can now attach the wires to factory looms and run them up through the kick panel. I used a lot of zip ties and an under the vehicle I used edel clamps. Be careful not to get the wires bound up on the parking brake arm or sprocket and keep them clear of this so they do not ground out over time. Then with the factory a pillar cover removed (just pulls off) you will see a slot to the bottom of the dash. I threaded a coat hanger down through the slot and taped all of my wiring to the hanger. I then slowly and gently, (important to not snag factory wiring), pulled the coat hanger and my wiring up through the slot. Then I was able to attach the wires to the gauges. I cut holes in the factory panel and threaded the wires through this panel to the gauges. As for the mounting of the gauge pillar, it mounts to the factory cover - Autometer provides small Christmas tree plugs, I hate those things. I used rivets and a rivet gun so it would all stay tight. The factory push tabs on the back of the factory cover are enough to support all four gauges without any issues.

Lighting - I used a test light to find the Ford wire that powered the factory instrument panel from the light switch. I then removed the factory switch and soldered another lead to this point and used this lead to provide my lighting power to the new gauges. This provides me with a dimmer and one switch does all operation. (I also, load tested the switch to make sure it could handle the draw - no problem). One other thing, I drilled a small hole near each gauge and installed a micro toggle switch in each hole, this allows me to turn on/off each gauge light individually if I want and leave my Instrument Panel lights on.

The install came out great, it takes about 1 full day for wiring and it took me about 4 hours to modify the gauge mounts and get everything set for the install. Cost was about $500.