Thanks, Neal. And Patrick, welcome to the forum. If you just want to make a fairly realist weathering of the chassis I would suggest you check out the work of MrObsessive and Mr. Cruz, and a few others . . . you just fog a little bit of overspray around the edges of the chassis.
If you want to go all out on weathering, then yes, I would suggest watching a few of the vids from EYEGORE's Gunk University Lecture Series! LOL!