You can remove the oil pressure switch and add a sender. It is located by the oil filter (the larger silver switch not the smaller gold which is for temp). I ordered this adapter and will keep the oem switch and attach the new sender - probably good to have double protection. This adapter will fit right on the 370Z (1/8 PT) however most aftermarket senders are 1/8 NPT and you need an adapter for that thread.
NISMO Oil Tee Adapter for Oil Pressure Gauge :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com