I know most of this stuff is answered elsewhere in this forum, but I wanted to get it all in one place and it may help somebody else too... I bought a brand new (0 miles) 2008 CRF450X. I have modified suspension and bars so far, that's it. I am a reasonably experienced rider. I ride exclusively around 1000 ft. above sea level and generally between 60 and 90 degrees. I have been experiencing the lean and performance issues everyone seems to talk about in this forum. I am going to be taking this advice, but just want to make sure I have all of my facts straight and want ask a couple questions. Pretty much everybody agrees the JD jet kit is a must. - Does that come with a finger-adjustable fuel screw or do I need to get one of those as well? - Where would you suggest to get it? (Best price) Sounds like I need a new leak jet. Should I use 55 or 50? OEM or Aftermarket? Anti-smog block-off kit. I can ride legally without it, which is the best one? Best place to get? (Best price) Air box mods. Is the just the top enough or do I HAVE to do the sides too? - I read something about removing an anti-backfire cage. What's that? Does it help. - Twin Air? It sounds like Accel Pump mods are not necessary on an '08, is that true? Anything else I NEED to do to make this this bad boy purr like a tiger? Thank you, in advance, for your advice and answers.