I'm getting ready to change my transmission fluid and rear end fluid and looking to go fully synthetic and using Royal Purple.  I will be towing with these oils.  04 Silverado.  

Any of you guys use it?  Pros Cons?

We use it in the gear ends of our big triplex pumps. On one rig it has been in them for over a year and a half with no breakdown of oil. We send samples in for evaluation after so many hours. These pumps run 24 hrs a day. So i believe it's pretty good stuff.

Pro's yes....

Con's: 1.Price.

         2.Has a tendency to leak in boosted applications (turbo or supercharged engines) but I have found this to be true for all synthetics.

Use it in the race car and the street car.

No boosters or chargers here.  Just straight motor.  

From everything I'm hearing its great stuff.

This oil was originally marketed as an API approved oil. In pumps that have oil rings made of bronze for lubrication in bearing housings they were concerned about black oil. Normal detergent oil would break down the bronze and blacken (containment) the oil. Also Royal Purple resisted condensation which was a plus in the pipeline industry which is subjected to change of season. I would think this might be a good alternative.

My brother has been using it on his 2000 chevy Z71, he combined the oil with the antifreeze as well, says his truck has been running much cooler and been given him better gas mileage of course due to this.

So far except price its had a good feed back ratio

Thanks alot guys.

The price isnt a big issue.  I'm use to using mobil 1 syn for motor oil.  

Sounding like the oil is one of the best out there.

I'm looking at this as

Motor oil syn  boosted mpg

so if I change the tranny and rear diff fluid it should boost some too. Plus I need to do it.

Royal Purple is the chit.   I have been using it in my stuff for about 4 years now.   I started using it when I noticed most all the race teams at the track used it exclusively and most of the teams that came in with the touring series used it.

Royal Purple motor oil is awesome, i use it every oil change and love it. Being a repair shop owner I also advise all my customers to use it.

My dad has used amsoil, royal purple, mobile 1, and elf . synthetic in his car which is boosted he claims elf was the best of all the ones he has used. Little pricey bout 11 dollars a quart.

european oil is higher grade it is used in porsches, bmw, mercedes so is nippon oil http://www.elflubricants.ca/index.cfm?fuseaction=main.display&Content=AutomotiveProductOverview

Is this rumor true, once you put synthetic oil in your motor you can't go back to the non-synthetic oil?  Unless you want problems :-?

just doesn't seem believeable