First off you have a good stock setup. Buy a new oil pressure sender and coolant temp senders. Then get the following:
-Press/Vac -Oil Temp -Timer
Just my thoughts.
"The 300ZX Turbo is a dance; it's a song; it's rolling, roaring automotive art. There is no color that doesn't suit it. There is no mood-lifting chemical substance it can't replace." - Automobile Magazine