Opinions/experience with Royal Purple or Red Line oils/lubes/ATF?

NüR-SPEC said:

redline motor oil is garbage. the gear fluids are fine, but the oil sacrafices protection to reduce drag and net a few hp. not worth grinding the lobes down on your cams and demolishing your piston rings. mobil1, motul, and lubrimoly are great products from the results i've seen in independant studies.

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I just visited Diesel Giant and his oil change page shows Amsoil. No-one using the Purple stuff? If you'd normally stick to 3K or even 5k mi. change schedule, seems you'd have to go waaay more to justify the added cost. Unless there's some proof one of the synth oils does something magic, I'll probably just go with the lowest priced 20W50 and regular changes.

How often does the engine oil get changed? Have you used any of the other BG (or anyone else's) products to compare performance?