Here is the setup I've been using for the last 18 months:
I don't like the "long T trees" as they vibrate like a ruler on the edge of a desk due to engine vibration and they can get very close to the serpentine belt. If the belt breaks (not common) it can break off the oil pressure T and you will have a bad day.
Also, the factory oil pressure switch only turns on the low oil pressure light when oil pressure is less than 5 psi. (bench tested)
You will have cam phasing errors (P0011, P0021) way before that light turns on... AND with the factory ECU, it doesn't use it in any way. Mine has been unplugged for 18 months and I monitor oil pressure using a Arduino based LCD display and now the GTR "MFD" gauges using my nav screen.
With the 90 degree fitting, I can support the other end of the oil pressure sensor, to prevent it vibrating and it is a little protected under the alternator, far away from the belt.
Anyways, there are many ways to do this and here is one more
