94TA oil and rear diff recommendation

[MS94TA]

Hey, guys:

The car is stock, has 36k miles. I use it as a daily driver. I'm not planning to do any internal mods anytime soon but do you all recommend synthetic or should I stick with regular 5-30w oil?

Also, the diff fluid is real dirty. Time to change. Any recommendations as to fluids for this? Any additives?

Thanks!

Martin
Utah

[Joe 1320]

Mobil 1 synthetic gets my vote. I just tore down the engine doing headgaskets. 123K daily driven miles and mobil 1 synthetic changed every 3K miles. The cylinder walls still had the crosshatch hone, no visible wear. I swear by the stuff. As far as the rear, synthetic oil too. Don't forget a bottle of the GM limited slip lube. Without it, the rear will start making noises.