Hello all, I've been visiting the site on and off for many years and finally decided to register to ask some questions. Vehicle I'm asking about: 2006 Jeep Grand Cherokee 4.7 V8 (Not the same as the earlier Jeep/Dodge 4.7s that had more sludging issues) w/ 6 quart sump, 101k miles Driving conditions: About 10-12k a year during my ownership, quite a bit of suburban short/medium trips (8-15 miles) with longer highway drives pretty regularly. Pretty mild climate with winter temps usually staying above freezing, although cold snaps sometimes have me driving in 20-25 degree weather. Previous oil changes: Manual calls for API 5W30 meeting MS6395, but I'm well out of warranty, so not really concerned about the Chrysler spec since all the oils I consider likely either meet or exceed it, certified or not. I've been using M1 EP 5W30 for about 40k miles with no complaints, aiming for changes around 8-10k, but my last OCI was 12k due to bad weather and laziness. Started using M1 filters when I started using the EP, but last time I changed the oil I decided to go with a Fram Ultra that’s currently still on there and may stay on for another OCI. The oil in there currently has about 8k on it, and I've only had to add half a quart recently to get it back into the middle of the "safe" zone on the dipstick, where it was right after the oil change. Looking at changing it now while the weather is decent. Even though I know real cold weather isn't really a concern in my location, the significantly lower temps lately have me curious about possibly trying a thinner oil. I really doubt I'll see much difference one way or another, especially one that could be measured, but I'm an experimenter and all the "thin is in" posts over the years are certainly intriguing to an experimenter. The 2007 model year Grand Cherokee (and equivalent Dodge) changed oil spec to 5W20, with the reasons much debated online. I do not believe that there were any changes to the engines that year other than some V8 flex fuel engines being available. 2008 saw an updated V8 with significantly more HP and torque. So with all that being said, I'm thinking I should be safe using a 5W20 or even 0W20, right? Considering picking up some PP 5W20 at WalMart since it’s on rebate, or sticking with M1EP and trying out their 0W20. Yes, I know that a good conventional like PYB changed twice a year would probably be more than satisfactory for me and my conditions, but even if there weren’t rebates that narrowed or eliminated the cost gap, I still wouldn’t fret over spending an extra 20 dollars or so on an oil change, even if the benefits are mostly psychological. Any risks I should be concerned about going thinner, or thoughts on the oils I’m considering? Thanks!