Lets get something out in the open here.
People recommend fatty's, that is not an mx pipe. The gnarly is the fmf mx pipe. FMF claims the fatty and the sst to have gains everywhere. We all know this is not possible for a 2 stroke pipe like the fatty to have a healthy increase everywhere.
When you say gold series, in my mind you are referring to the old pipe made in the mid 90's. Now I realize that the fatty says gold series on it, but so does the sst and and the gnarly. So in my mind, gold series was the pipe made in the mid 90's that only had one name, and that was "Gold Series".
DG pipes are loud, and hard to get replacement parts for. T5 is a mid-top pipe.