my turbo is starting to turn a darker shade of tan. is this normal ? i have 40,000 miles,slightly modified, boost upwards of 30 lbs. have i over heated it? anything to worry about?also on the intake side of the turbine wheel it looks like it has a tiny weld spot? id this how they balance them. the truck runs great ,i pull a toy hauler up grades of 6% at 4400 ft altitude .