[niterydr]

The key to running different oil weights is to keep two things in mind:
1) Target oil pressure at different RPM points. To little pressure and you end up with starvation, to much and you run into other issues. You want enough flow to lubricate at all rpm points, pressure is just a common measurement to watch for restrictions. Flow is the key here, but pressure is a good point of reference for most setups.
2) Ensure you have enough oil thickness at high temperatures. It is common for many "race" cars to run two weights of oil, one on the street, and one on the track.

If you are running a 20w-50, there is no reason you can't switch to a synthetic 5W50 and enjoy a better flowing "cold" oil with the same protection up top. Most of your damage, if your oil system is up to snuff otherwise, occurs at cold start.