For those of us owning an 85' or an 86' 250R, we are limited with exhaust options. FMF is pretty much the only new exhaust currently available. So I got to looking at the mufflers FMF makes for the 85' & 86'. I found power core and power core 2, and I may have seen a turbine muffler as well, my question is, what's the differences between FMF models? If any.