I have read numerous things regarding shock fluid used to replace the old fluid in factory rear shock. I know Murphskits.com sells a "rear shock oil change kit" with some plastic beakers and also some fluid, but his website doesn't list what weight of fluid this is. Has anyone used this kit and if so, what weight and specs are the fluid? (their site only gives a viscosity index) Does it make the ride much stiffer than the OEM fluid? I shot them an email and waiting for a reply but figured I'd check here and see if anyone has any input. What other 10w or 15w "shock fluid" has anyone used? (not atf) who even makes a 10w "shock fluid"...(not fork oil)