I'm kinda sceptical about it, heard it's not all that great and ends up creating sludge or something, don't remember exactly. I don't have a Nissan, but a Celica with 180k miles on it that takes a bit of oil, and i'm running good ole Castrol GTX 10w-40.
Anyway here's some info I dug up from a different board:
"High Mileage oil is crap. Don't ever, ever use it. All it does is cling to particles in your engine and bond them together and it coats everything in a thick oil type shell, so it really doesn't flow as it should. It's mainly meant for engines that are already burning off oil at starts and have no more than 1,000 miles left, it's mainly a last attempt to get a couple more miles off a dying engine. So just use regular oil!! "
"i used high mileage oil in my mitsubishi 1 month before i rebuilt it and the machinist could tell i used it cause he got about 2 gallons of sludge out when he hot tanked the engine..that **** can wear out moving parts prematurely as well as raise oil pressure and blow seals(i experienced this),even in a good engine with lots of miles left..."
"all high mileage oil does is bond particles in the oil and coat everything (so it flows like crap...literally) and that's how it stops up leaks, it's SLUDGY!!!!!! How can any oil leak when it's like sludge? Don't ever use the stuff. If your engine is dying just get it rebiult or get a newer one, but don't use that high mileage crap."
"used castrol hi mileage,and the machinist says that hi mileage oil or synthetic oil is the culprit for the sludge because it is formulated to bond to moving parts and cracks(fill voids such as oil return holes and oiling holes for main bearings and rods and cams)..i believe him,but i havent ever tried maxlife oil,i just stick to regular 10w30 and run a quart bottle through the engine on oil changes(to flush it)..i agree with you about the "miracle" additives(like no smoke,that stuff is thicker than 80/90 gear oil)...the best thing to do when an engine starts showing signs of wear is to rebuild or replace it...or blow it up

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That convinced me pretty much not to use it, and stick with what works unless someone knows otherwise.