Hi, I have a 76’ 280z and I wanted to do some performance upgrades. However, I have no idea where to start. The previous owner did some work but I do not really understand what he did or why. What I do know is that he made his own aluminum fuel rail with larger injectors, he didn’t specify. It’s also has a 5 speed zx swap. The car runs extremely well the previous owner had the car for 10+ years. The first thing I have started on is a exhaust. I want to do a 3 in all the way from the headers with a Magnaflow muffler at the end, still haven’t decided which. Any recommendations on that? Also should I upgrade my headers? I am 16 so I am learning about the mechanics on this car. Also the car is freshly painted here are some pictures below.