I'm getting ready to do the shock upgrade. Are people finding that the parts you have to re-use are ok? I'm talking about the Spring Insulator - GM (15808594), the Front Spring Upper Seat - GM (15803177), and the Suspension Strut Bumper - GM (22830628). If people are finding that these need to be replaced, I'd rather have them in advance than have to order or hunt them down. Thanks