Pipes on two-strokes were a must-have just a few short years ago. But the stuff coming stock has slowly become really good, especially from KTM. This forced FMF back to the drawing board on a number of its KTM pipes and specifically on the 150 SX. Although the KTM 125/144 pipe would work just fine, the two-stroke expansion-chamber-heads at the Flying Machine Factory knew there was a bit more to be had, even when put against a stock pipe and muffler that are tough to beat.Well, I put the combination to the test, and I need every ounce of power I can get out of that little screamer for my 185-pound chassis. The fit was spot-on, and it took less than 10 minutes to switch out the pipe and muffler. The muffler now includes the rubber grommets, and the pipe has O-rings already installed. The first thing we noticed was a crisper sound out of the slightly shorter muffler. It was just a tick louder to the ear than the quiet stock muffler through the rev range, yet was still under 96 decibels in the 20-inch test. It did not make the bike offensive like a shorty muffler would and was plenty respectable even considering the sound of the two-stroke does not carry like a thumper's does. The power increase was a little harder to feel but was definitely there. As a combination, the FMF setup gave the KTM a little more hit on the bottom, slightly better pull in each gear and just a smidgen more power on top.