Hey there after the break I am going to start doing some body and paint work on my car and just try to make it super clean. I also got a lip kit to throw on the car here in a few weeks. The problem I have is the car has already been painted once its currently two tone with a different shade of blue ( fades to purple when sun is going down ) and black. I wanna repaint the entire car engine bay and trunk area an HKS style purple or a TCU purple. I need to know wether I can just scuff and paint or wether I have to take it down to the original paint job and scuff that one down and then paint for a cleaner look. I have two instructors here at wyotech that told me to do it different so I am trying to figure out what should I do. any suggestions ?

Wipe it down with degreaser, and just scuff and shoot it. Thats if the paint is in good shape and not flaking off

Well if the new paint is a specialty paint, then if it were me, I would remove the previous paint as much as I can then spray. If its a paint that requires several layers, you wouldn't want to lay down the layers unevenly and inadequately and have the underlying paint you didn't remove completely to show. Maybe its just me though. I spot imperfections down to the molecule lol.