Just got my new manual for my 07' XRL. I had a 93' manual from when I had a 93'. I ran into some problems when I replaced my left side cover, the 93' manual showed some things that were not on the newer model. Anyway's, the old manual had a graph that showed all the different weights of oil that you could use compared with the temp. of your operating area. The old manual said you could use 20w-50 safely for higher temps. The new manual shows only 10w-30 and 10w-40 as the only oils that you SHOULD use. I'm assuming this has more to do with fuel economy than anything else, bit I have HEARD that it COULD be from closer machining tolerances. I'm thinking the former not the later. Anyone think I shouldn't run 20w-50 in the summer weather? It's been pretty dang hot here in OH, and I am going to 10w-40 this fall. So, what do you think?