Also go take a look at the UOA forum on this site. LOTS of UOAs of RTS 5w40 ao you can see how the viscosity and TBN holds up over time/miles, and a at least one thread discussing the (rather odd) difference between the SL/CI version and the new SM/CJ version. I say "odd" because while you might expect a big reduction in Zn and P, what seems to be the most different is the calcium/magnesium ratio. A confounding factor is that it appears some people may be mistaken about which version of the oil they actually had, since RTS changed to a new bottle design *before* changing to SM... so you really have to look at the little API circle to know what's in the bottle.
