I'm interested in getting my 22 year old Silverado 4X2 5.0 liter ECM overhauled. If you search the net you'll come up with a lot of rebuilders. The only one I contacted was AES module rebuilders. The guy I spoke with was real friendly and answered most all my questions. But I was just wondering if any of you have ever undertaken this kind of overhaul before? Any tips are most welcome.