I have the FMF PowerCore SA for the CRF230F. I bought it used on eBay from Dennis Kirk when my stock exhaust was damaged.
I don't like to "bad mouth" products, but you asked: I am very disappointed with my FMF product. I am so disappointed, that I am putting the stock Honda exhaust back on my bike; performance or not.
The FMF pipe is loud, but gives the bike LOTS of power! I found the noise level objectionable, so I repacked the muffler, which did not quiet it any. Some time later, the spark arrestor "blew out" and I could find no way to fix it. I could not find any spare parts for my particular muffler on FMF's website nor at Dennis Kirk, so the spark arrestor is not fixed.
After taking apart the entire pipe, either to repack it or "fix" the spark arrestor, I know the FMF pipe inside and out. I am very displeased with the design of it; it is basically a metal tube (mid-pipe) that continues through a perforated tube with packing material wrapped around it, and ending with a steel screen (like window screen) for a spark arrestor. There is really only the wire screen to impede the airflow, and when the exhaust pressure builds up enough it actually "blows" a hole in the screen. The screen is tackwelded to the steel tip at the back; there is no way to screw or bolt on a new spark arrestor.
Sorry to be so long winded, but I've been installing aftermarket exhausts for a long time and I paid a considerable amount of money on this FMF pipe. I don't know about FMF's other products, you might be pleased with them. But for me, I was disappointed and its coming off my bike!