OK, I wasn't going to say anything, but I couldn't help myself.... SERIOUSLY man?! You join this forum and your first post is to revive a thread from 2007 just to bash the person(s) idea of removing a baffle...? And to top that off, your arguments on the subject aren't even 100% accurate. Yes, maybe on 2-stroke bikes were having a good amount of back pressure is important you may actually see a decrease in power by removing a baffle, but on 4-strokes its been proven that a free flowing system will increase power with proper jetting. How much power, probably not much, probably not even noticeable in the "seat of your pants dyno", but it does increase power. As for someone spending $2,000 on a pipe, jetting, filter, and ignition, I SERIOUSLY doubt anyone is dropping that kind of cash for just those items, and if they are its because they already have a ton of money into the motor itself and just want every last ounce of power they can get. As for your question "is it really worth spending $2000. for 5hp more?", to some people I'm sure it is. If your quad only comes with about 28hp (such as a stock 400ex), 5 more HP is almost a 20% increase in power and will be very noticeable on something that only weights 375 pounds. Doing all these things, if done properly and with correct jetting, will not make your bike ANY less reliable then a completely stock bike. In fact, it may actually be MORE reliable because in the case of the 400ex, they come from the factory jetted on the lean side. So after you dial in the jets better it will be more reliable.