A couple of days ago some people replied to a post saying that you can mix different viscoscity oil without any harmful affects. So tell me, if I mix 20W-50 with 5W-50, does that make my oil somewhere in between 5 and 20? Or doesn't it work like that?

I would only recommend mixing oil when you don't have the original viscosity and need to fill up in an emergency. With the quality and variety of oil, it's really a fool's game trying to outguess the oil chemists (and chemical engineers!) and come up with your own mixture that will work over a broader temperature range. Follow the manufacturer's recommendations and you can't go far wrong.<p>Steve