If I was going to buy any of the FMF pipes for a 250 I would buy the Gnarly pipe. From what I have read it would give the best power output for my style of riding, tracks, woods, desert. Just my $.02.

 

Depends on how and where you ride if you ride a lot of motocross in the upper revs I would recomend the SST: http://www.fmfracing.com/products/catalog.aspx?CategoryID=55&ItemID=020166
If you ride Motocross and lag at the end I would recommend Factory Fatty: http://www.fmfracing.com/products/catalog.aspx?CategoryID=56&ItemID=020054
Or the regular Fatty
http://www.fmfracing.com/products/catalog.aspx?CategoryID=56&ItemID=020054
Or if you ride trails or just slow in the lower revs this the Gnarly: http://www.fmfracing.com/products/catalog.aspx?CategoryID=57&ItemID=020059

 

I've got a pro circuit platinum and r 304 silencer and it made my bike faster (01 kx 250)but more in mid range and above.Still no way id go back to stock.

 

hiya people im looking for a new exhaust system for my 2000 kx250 the fmf range have caught my eye but theres so many to choose from so far i facy the fatty front pipe with the powercore 2 tail pipe can anyone tell me if this is a good choice or is there better cheers wayne

Since many pipes are tuned to make their best power in a specific part of the band, it would be wise to research various pipes to see where they are designed to make optimum performance. Then you need to determine just where you wish to see improvement in the band; low, mid range, or top end.
I was always happy with the Pro Circuit line of pipes which were designed for the mid range part of the band and they seem to maintain their appearance quite well with no rusting or discoloration.

 

True FMF makes some great pipes. On my CR500 I had an FMF "Burley" pipe (before they called'm Gnarley) and the Powercore II silencer. Really great down low and good mid range punch, but flat on top. Then I switched over to the Pro Circut Factory pipe,still with the FMF silencer. WOW. It really made that 500 come to life! I'f you're riding woods, use the FMF, if your riding MX, Pro Circut. There's more, but that's all I'm familiar with.