I'd like to add my opinion; I'm an Amsoil fan,
http://www.amsoil.com/ , I like the research they do to stand behind there products. They don't just sell oil products but the whole lubrication family is involved. To take their love of engine protection to the next level they also provide a remote oil filter and a by-pass filter system. The by-pass filter will filter 100% of your oil every 5 minutes down to
1 micro!
http://www.amsoil.com/a/By-Pass-Filters-Mounts
The product line goes one better for those looking for the best in preventing wear...a 160cc preoiler that provides oil pressure prior to starting the engine.
http://www.amsoil.com/storefront/amk.aspx