As someone who is "infamous" for asking for REPUTIBLE sources to link to, I have to tenativly agree: I'd like to see sources. There's more claims about oil than there is oil out there.

Even in this post, I've still seen nothing that says $20 Mobile 1 is twice as good at protecting than $11 Wal-Mart full synthetic except for Mobile's advertising campaign. Their own web page has nothing about it:
Mobile Oil Info

Before I'm bashed, I do have Mobile 1 synthetic in my new Rodeo. (For now!) But in my 1993, 167k mile 2.6 Amigo, it's Dino-oil all the way. And for the last 67k it's been Wal-Mart Cheap-o Dino-oil at that, with 5k-6k on oil changes. For normal drivers (high-stress applications aren't an every-week thing), synthetic really doesn't seem to have any advantages over Dino oil. I don't mind saving $15/5 quarts over a 15 year lifetime that I'm going to get of the Amigo. (And a new car is nice after 15 years). $20 Synthetic seems (as there's no proof at all) only marginally better than $11 synthetic, especially if it's the same base stocks and have 99.5% of the same goverment-mandated additaves for the star-stamp.

I'm factoring the above posts and info against the July 1996 Consumers Reports oil test. They took 75 new NYC taxicabs and measured all the "high wear" areas in the engine. They used regular and synthetic oil (including Mobile 1), 3k and 6k changes. Summary: No noticible differences in wear in 3k or 6k chanes. Barely noticeable (with micrometer) difference between Mobile 1 synthetic and regular oil

(Lots of idleing time; really tough on an engine--see your Isuzu owners manual; it defines heavy towing and extended idling as the heavy-duty operations that require more frequent servicing)
Most of CR article at: http://www.scuderiaciriani.com/rx7/oil.html
(further googling could probably turn up the whole thing)