Im getting surgery on my shoulder in a few weeks and will be selling my 250F to get a 08 YZ450F, I already know the stock muffler sucks big time and basically im looking to start putting together a budget list of must haves so my bike will be ready to go as soon as im strong enough to start riding again. The only thing I need help with is the exhaust. I want to increase the bottom end on the bike for sure, and if the mid-top transition stays the same as stock or is improved that would be perfect for me as I like to shift early and ride out the power. But, I want a quiet slip on pipe, I have had excellent experience in the past with FMF so I will stick with that, but it must be as quiet as stock or quieter. I was looking at the Q4 by FMF, has anyone tried that? Can the spark arrestor be removed? I only ride track, but am a big fan of keeping tracks from being banned and want to keep the bike quiet while improving the power.