I fully realize that this may seem to be a simple enough job for most import enthusiasts, there are a few things to consider in the plumbing process.

I'd like to point out that we've seen many engines over the past few years with broken oil pressure fittings and internal damage, that we should take a hard look at the situation.

The accepted conventional way of plumbing these gauges has been to add a "T" fitting to the side of the block, with the tap at the stock oil pressure sensor's location on the block. 

It all looks easy enough, but consider the weight of the brass "T" blocks that are used. When this mass is hung even a short distance from the block, the famous 4 cylinder's vibration can quickly work harden the brass resulting in a catastrophe if the driver's not right on top of things.

Here's a picture of one of the "conventional" methods for plumbing the oil pressure source for gauges as well as for feeding "other" oil hungry accessories.

Note the distance between the block and the end of the assembly. Perhaps, in this   view, you can see why it's a dangerous combination. 

This next illustration shows the configuration that we prefer to use at Endyn.

Please forgive my "art work", but it should be readily apparent this method removes almost all the stress on the block at the point of connection. The best place to mount the brass "T" block and the respective taps is on the firewall. The connection between the block and the "T" can be with either nylon tubing or braided steel. It's important to make sure that the connecting line is not tight. Putting a lot of slack, or a loop for strain relief will insure that the engine can vibrate and "rock 'n roll" all it desires without causing any problems.

This photo shows a "T" block used for an oil pressure gauge that's tie wrapped to the brake line junction on the firewall. Please forgive my use of hose clamps, but they won't show up on ET slips and the car's not meant for show.... just good dependable daily transportation!