Actually the plug holes are the same. All of the cases are the same for all of the XXL's. The differences are I believe the type and amount of filtering. I have a XXL that I purchased when I had a 3PJ. I sold the 3PJ, and got into a R1. Still works fine in most of my cars, using the R1. I know its not the best reciever I have so its in a car that I just use for play, but even in racing with 9 other cars on track, still had no glitching...