I thought this might be useful to post here: A little bit about me, I’m a 36 year old vet B/C weekend MX racer. The 2 stroke is a 2006 RM250 that I picked up in July of last summer for $2500. It was box stock and had about 10 hours on. It was in excellent condition. I was coming off a 6 year absence from riding and I just wanted to get something cheap in case I decided that I made the right choice 6 years earlier by giving up (previous bike was a 2003 CRF450). I went to my first local race that weekend and I was hooked all over again. After the season I ordered a 2011 RMZ450 but after about a month my dealer told me that they couldn’t get one. Since I had my heart set on the RMZ, I figured I would wait and just do some work to my 250 and ride it one more year. Here are the mods: -FMF Factory Fatty and shorty silencer -Eric Gorr 300cc kit with porting and head work - $600 -Factory Connection revalve and respring Eric does amazing work. The cylinder was rebored and plated and it looked perfect when I got it back. He had to modify the exhaust valve and reed cage for clearance. With the kit comes your choice of porting. The choices are bottom to mid, mid to top or a broader smoother power all the way from top to bottom. You also get your choice of head mods. Since I ran race fuel anyway, I chose to go with the high compression head and the broader more smooth power band. The RMZ450 is a 2011 that I picked up in December of last year but I didn’t ride it until about six weeks ago. I had already done the work to my 250 because I was not expecting the bike to show up but out of the blue one arrived at my dealer so I grabbed it. Here are the mods: - Rekluse Core EXP 2.0 -Yoshimura RD4 Full Ti exhaust -Factory Connection revalve and respring I’ve got 7.4 hours on the 450 so far and the first thing I can tell you is thing just pulls and pulls and pulls. The pull is probably exaggerated by the traction. The back wheel feels glued to the track. Because of that it has roll on power everywhere. When cornering conventionally while using the clutch (which you can still do with the rekluse) it turns like it’s on rails. Since installing the rekluse I noticed that it pushes the front end a little bit more when you get lazy and just rely on the rekluse. I assume this is because the front end gets abruptly unloaded and light as opposed to gradually fed power with the clutch. I’m also running the stock tires so that might have something to do with it. In spite of this, the rekluse is the best mod you can do. The bike WILL NOT stall. I was having a problem stalling it at first because the clutch would not totally disengage. I was told that in order to have a real smooth and easy clutch pull they lengthened the pivot arm on the clutch. I’m not sure if this is true but if it is then in doing so they made it difficult to ride because the bike will stall if the clutch isn’t all the way to the bars. Rather than deal with it I just installed the rekluse and it is awesome. The RM300 is everything Eric Gorr said it would be. He told me I would ride a gear higher because the motor can pull it now. He told me that the horsepower would be well into the mid 50’s but it would feel weaker because the violent punch would be gone. He also said that because of the porting it would make peak hp a few hundred rpm above stock and pull smooth all the way there. He was 100% correct on everything he said. On tight bowl turns I would just come in, in 3rd gear, turn the front wheel down the bowl, feed it a tad bit of clutch and the motor would sing for as long as you wanted to hold it open. It doesn’t have the 450 roll on power but it’s probably as close as you will get out of a modern 2 stroke. As far as handling, it was not affected at all by the mods. The thing turns ridiculously and it sticks in the rutted turns better than any bike I’ve ever ridden. Conclusion: The 450 is an awesome bike and it handles and turns as good as any 4 stroke I have ridden. It has power everywhere and is a blast to ride BUT, the 2 stroke with the big bore has more than enough power to keep up at the level I ride at, it handles better and is about 30 pounds lighter. So far, I would have to say the 2 stroke is more fun. I timed a few laps on each at my local track and I’m faster on the 2 stroke after the mods. More power on a 2 stroke usually means more out of control or harder to ride. That’s not the case with the big bore. It’s is noticeably more power than stock but the power is dispersed so evenly and in places where I can use it more effectively that the bike is actually easier for me to ride. I only have about 7 hours on the 450 so I might get better on it with time and change my mind but for now, the 2 stroke is my favorite of the 2.