Water / oil pressure gauge help?

For the oil pressure sender, you can use a T fitting and retain the stock sender.

For the Water Temp, there should be a threaded plug on the top of the thermostat housing(driver side top front). You can use adapter fittings and put the sender there.

There are 2 problems with using mechanical guages though. The biggest problem we ran into when putting guages in an '05 GT was getting the senders through the firewall and into the engine bay. The grommets for the existing wiring harnesses go through the firewall low and come out inside the fenderwells. Its hard to fish wires through there, and near impossible to get big sending units through. The other problem is that with a mechanical oil pressure guage, if you get a leak, you can get a BUNCH of oil everywhere before you know it. If the leak is inside the car it would really suck.

I know that the mechanical guages are much less expensive, but IMHO, if you can afford it, go with electrical guages......they will be much easier to install, and much more reliable.