I thought long and hard before ordering my Fatty pipe for my 01 CR250. Like kawicam250 said, its all about preference. I like bottom end on my bike, so I went with the Fatty.
If you ride the woods a lot the Fatty might be your better choice....
There all good pipes, you just have to figure out where you want the power and get the pipe that puts it where you want it.
Fatty: Offers broad and substantial power enhancements throughout the performance range. Bottom power and meatier mid-range with an impressive top-end gain maxing out at a 10% horsepower gain.
SST: Up to a 15% horsepower gain can be achieved. It gives big gains down low, a quicker and harder hitting mid-range with the top-end that revs hard and long.
It seems like they both increase bottom end, but the SST gains 5% more horsepower.
I still dont know which one to get for myself.
We ran an SST on my sons RM125 and were happy with the gains, 15% is a pipe dream however, pun intended. If you go with the SST keep an eye out for detonation as we experienced some with ours and it's a common issue with the SST setup.
The SST pipe increases mid range pull and extends the over-rev considerably while sharpening the off idle throttle response. No other pipe on the market can offer these same type of gains or offer the same linear power delivery that the patented SST brings to the table.
Our Fatty Gold Series pipe broadens the powerband and provides a healthy power increase everywhere. Improved throttle response, a linear powerband and enhanced over-rev all add up to a pipe that everyone will benefit from. The Fatty pipe is our most popular pipe for that same reason. If you’re riding trails, tracks or in the open desert, this pipe has what you’re looking for.