I have a 2002 nissan sentra with a 3.5 maxima swap, i am currently running Mobil 1 10w40 HM and a Mobil 1 filter 3000 Miles on it right now seems to be doing fine. Reason for the heavy weight is the inherent oil consumption of the vq35 and the summer heat, i was running RP 5w30 and it was guzzling it like it was an alcoholic, on top of that my motor was running hot so it was a no brainer to switch to a heavier oil. BTW the motor is golden 175-180 psi of compression on each cylinder, coolant just flushed no problems there. TO get to the point i have read on the forum that people have been using rotella 5w40 t6 how is it? Its getting colder in ny got to make a decision on which oil to use . Thanks guys