I am looking into picking up a bike in the near future, and kind of have my heard set on either a 2010 or 2011 kx450f. Before we go to far however, I'll tell you a bit about myself. I'm 20 years old, weigh 160 and am 6' tall. I have grown up on and off of motorcycles, however never to a competitive or steady season. We have had a bike or two in my family all along however they were always just two wheels and a motor so to speak, nothing special just a field beater if you will. I have ridden a couple proper bikes, street and trail to motocross and even some big street bikes. While I am fairly inexperienced on a motorcycle, I have an extensive downhill mountain bike racing background. I have excellent bike handling skills and ride at quite a competitive level. I am comfortable hitting 40 foot gaps on a downhill bike, and speeds of 30 mph are not uncommon (mind you it's not a groomed trail we are talking about). So, I am looking at adding a little motocross to my arsenal of summer activities. I wan't a bike that I am not going to find myself growing bored of in a season, I am a rather aggressive rider on a downhill bike and have never been one to be afraid of what a moto can throw at me, I know enough to get out of trouble should I find myself to deep in the throttle. Putting a lot of power to the ground is something else I am used to, being into muscle cars and whatnot. I live in a city which has a public track open 5 days a week, so it would not be uncommon for me to log 5 or 6 hours a week on top of riding my downhill bike. Like I say, I am an aggressive rider and don't back down from much, I really aim to perfect techniques and lap times. I also have a fairly good mechanical background, I do all of my own suspension tunning/re valving on the little brother to the moto suspension (yup, its nearly identicle in mini scale), as well as all other maintenance on my cars and bicycles, and yes it requires a silly amount of work to maintain a downhill race bike. I've done a bit of reading on the KX450's of the '10 and '11 model years and it sounds like there is quite a difference between the two. I like the idea of the programmable ECU on the 2011, but what are your opinions on the adjustments they have made to the swing arm and steering portion of the frame (head tube and fork steerer tube??). From what I've gathered they have relieved some of the rigidity in these areas, supposedly improving handling? Any input on this area? What are the rebuild intervals like on these bikes? As I said I am pretty handy with a wrench but I don't want to be replacing pistons every other week or anything abnormal compared to other bikes. Lastly, perhaps I am a little "blinded by the light" and I should look at other makes and models. What are the major differences between brands (kawasaki, honda, yamaha ect.)? With downhill bikes no two frames or bikes or component is even close to the same, however at a quick glance things seem to be fairly similar in the world of motocross. Everyone seems to have very comparable products, or do I just need to dig a little deeper? To sum it up, I'm a young guy who loves going fast, has minor motorcycle history but very extensive downhill mountainbike racing history. Know my way around most anything mechanical with a wrench and or hammer and love a challenge, hate getting bored of something in a short amount of time and need a motocross rig in the near future. Any help would be awesome and sorry for the 15 mile long post.