I'm no expert on the subject but I would say to install one or the other. I would say the plate ($35) over the Dyna Tek ($250). Since the objective of each item is mainly to alter timing, using one of the 2 mods would be sufficient. As I said i'm no expert but I would think that if he were to install both and andvance the timing on each, say 4 degrees, he would end up with an 8 degree advance. Somebody correct me if i'm wrong. Also, find out what he means by "already timed".