What do you use? Options

[turbohcar]

I know it's been talked about before, but I'd like to go a little more in-depth. Oil. Which grade to be more specific. I've read a couple VFAQs on it and had experience choosing oil (I change oil for a living at a Dodge dealership) for different vehicles. However, the only vehicle I am concerned about with this post is the 4G63T motor. Post what you use and why you use it. Like I said, brand isn't as important because most of the time it's a matter of opinion, it's more about the grade.
Right now I'm using Cenpeco 5w30. It's a paraffin wax based oil that is made for high performance vehicles. Pretty expensive but worth the price for an all race motor. I'll be switching to Valvoline Synthetic here the next oil change but I'm not sure yet which thickness. Thanks

[turbohcar]

Mobil 1 is also another very good choice for oil blend sensitive motors that I've noticed (not to be confused with regular Mobil). Currently, the three tanks we have for oil at work are filled with Valvoline 10w30, Mobil 5w30, and Motorcraft 5w20. All of them seem to be reputable oils for dino oil. One motor oil I'll never use is Penzoil. It seems that something that is sold by Walmart in their oil change bays just isn't good enough for my car. That's just me talking though. I'm using the Mobil 5w30 in my S10 and it is rather happy with it. When I had 10w30 in it at first it really didn't seem to perform quite as well.

For the newer vehicles (100k or less miles and post 1990) I usually use the 5w30 unless otherwise specified. Anything older, more miles, or just in poor condition and I put the 10w30 in it. The 5w20 is mainly for Ford products from 2000 on and some 2005+ Dodge Caravans.

Alldata also says to use 20w20 or 20w40 for temperatures above freezing, 10w30 for temps -5 to 32 F, and 5w30 for anything below -5. Granted the source isn't entirely credible but can this really be true? I've also seen charts for the Turbo T/E/L that says 5w30 below freezing, 10w30 above. I guess this is the source of my confusion about which thickness to use.