About a year and a half ago I switched out all my fluids to AMSoil brand synthetics and WOW, what a difference! Immediately afterwards the ride and the shifting were noticably smoother, even though I had done all the scheduled maintenance with the types of products recommended by Isuzu.
More recently I've "downgraded" my oil to Mobil1 because I can get it for a lot less than AMSoil (about $20 for a 5-Quart Bottle at Walmart) and haven't noticed any difference. Although my research indicates that AMSoil is a superior product, Mobil1 also performs very well and is probably more than adequate for the way that I drive and maintain my VX.
I suppose synthetics may not be worth the money for your beater car, but this is your VX we're talking about here, man!!
Calmini Cone Air Filter, PowerVault PV2 Muffler, OME Trooper Springs, Rancho RS9000X Shocks, 285/75R16 Nitto Grappler AT's, Pioneer DEH P8000R In-Dash CD, Amps and Drivers Built by Orion, Wires and Fuse Blocks by KnuKonceptz, Vibration Damping by BQuiet, Alarm System featuring Auto Start and Remote Windows, Yakima LoadWarrior w/Full Size Spare, Debadged/Custom Titanium Grill Logo, Tint (5% Rear / 20% Front), Steel Braided Brake Lines, G2 Painted Calipers