All of the current four-stroke 250cc MX bikes are very good, but the others are a tick better than the unchanged-for-2006 RM-Z. In spite of the weaknesses of the bike, there are worthy reasons to buy one: It’s offered at a fair price and is backed by a strong contingency program. But if you are buying the bike to save money or to win some, it doesn’t make sense to spend a carload of cash making it hyper-competitive. The actual performance mods seen here are simple and reasonable.With just Hot Cams, a CP piston and an FMF pipe, the RM-Z engine came alive. I could tell the engine was stronger and more responsive when just warming it up! The power I heard in the pits followed right out onto the track. The stock RM-Z has strong, smooth power with no real hit. As long as you keep the rpm up in soft track conditions, it pulls well. Sink the bike into a berm or mud, though, and it is reluctant unless you slap it hard with the clutch. In contrast, the Hot Cams/CP bike snaps hard from much lower in the powerband, and you can feel confident staying a gear high into soft berms and mud ruts. There was no question the power would be there. The motor was strong and super-snappy right off the bottom, but it carried right through the midrange with no hesitation or dips in the power curve. It was awesome. We tested the Hot Cams bike at Glen Helen-always a fast track-on a muddy day, and from that we determined this motor is at its best on a tacky track with short runs to the obstacles. Until I learned to pull a tall gear, I felt the motor lacked a little way up top, where it is strong, but it was so good everywhere else that I just wanted more. With such a strong bottom and mid, riding a gear higher and short-shifting was a total advantage over the stock motor.The RG3 suspension took a little tuning to get settled-I raised the fork up in the clamp. But it definitely held up to pro speed while still keeping the wheels on the ground for traction.I know why we call these tests dream rides now. I had to give this bike back, and I’m dreaming of one like it to go with the RM-Z450 I race in the big-bore class.