Hi Just wanted to drop in my seal of approval for this oil.Its AWESOME. It was more than just an informed decision. Researched the choice for a good 3 months or so. Reading forums, product data sheets, oil analysis reports, compared the oil composition,pour points,viscosity index,heck even read amazon reviews. Heck, even Mike Miller-BMW expert uses Redline in his BMWs. Why 0w40 and why not 5w30. I live in Canada and if you are smart you would never use a 5w oil here, It pains me to see people running 5w and even 10w in their cars here,foolishly. Most of the wear in engines occurs at startup and more so coldstartup, 0w oils in extreme cold temps can reach the narrow passages, more crucially turbochargers much much much earlier and provide lubrication. Last winter I noticed that with the Bmw 5w30 the starts were pretty rough, and at times i had to hold on the start button for a while longer as I heard the starter furiously trying to crank, hindered by the thick peanutbutter in the sump at -30. 2.Why not Redline 0w30, why 40 weight. Well, our engines run hot and it is my belief (you may disagree with me), it is cheaper for BMW to specify and stock fewer weights of oil. I mean comeon..think about it,, all models from 320i to the M cars would use the same oil, especially when there is so much difference in output? Also, turbo engines are hard on oil and 30weight oils shear out of grade soon. Also with Direct injection, fuel dilution is also a concern, especially in cold climates and/or short trips. therefore a 40 wieght oil provides a better safety margin Also, if you drive your car hard, or track always choose a thicker weight for more protection due to elevated oil temps. I drive my car the way its meant to be driven, hard. BUTT DYNO READINGS. 1) Smoother starts This is noticeable from the get go, engine is quieter on startup. 2) Their is much less hesitation initially, you know there is some slugisshness in the first few miles you drive, well, its gone. 3) There is also this eagerness to rev, the engines wants to rev, this is the most noticeable aspect after the switch. I am guessing it has to do with Redlines ester base. There is much less fluid friction as esters have uniform size molecules and the oil has great flow properties at all temperatures thus creating less drag on the crankshaft. 4) Engine is quieter at high speeds, this is very noticeable at any speeds above 130..140..km/hr. I had also recently swithced my differential fluids to Redline 75w90 (although noticed no difference)..no problems yet. I also plan to do an ATF drain and refill with Redline D6 and Lubeguard Platnium additive, will provide a review. The Catch Well Redline oils are not BMW-LL-01 certified. Redline recommends its 5w30,0w40 and even 0w30 for our engines. My car is CPO but I took a leap of faith and got rewarded, my car loves it. I plan to do uoas and keep this thread updated. Question..I dont know where I read.. the initial UOAs of Redline are never stellar, it takes a few intervals for Redline to establish it chemistry and deliver excellent numbers, is that correct? Also should I expect the first switch to Redline will cause a slight spike in oil consumption,and that it would go away soon? One of the times I wish i had a dipstick.