I like the red and white one better. I'm using this picture as my monitor background right now, but don't have plans to buy one right away. If I had more friends that rode sport quads instead of utility quads I would have the first one I could get though. I think Yamaha hit the nail right on the head with this ATV.
Yamaha made some great upgrades to the YFZ when they created the YFZ 450R. This information is from Yamaha's Canadian web site:
Newly designed Dual Over Head Cam (DOHC) 449cc 4-stroke engine retains a 5-valve head for optimum high RPM power. Many of this engine's design elements have come directly from our race winning YZ450F and WR450F motocross bikes, including the cylinder, cylinder head, cams and crank. Engine power and mid-range response are both improved over last year's YFZ and with the addition of fuel injection, engine power is always optimized, regardless of altitude or temperature. The crankcases have been beefed up and the oil tank and lines are now integrated for improved durability and a lower center of mass. The new crankshaft has a larger diameter big end bearing, a stronger connecting rod and a smoother counter balancer.
Yamaha Fuel Injection (YFI) constantly monitors variables such as air temperature, intake pressure, engine temperature, throttle position and more, to ensure optimum fuel delivery. YFI automatically compensates for changes in temperature, elevation, and even barometric pressure. This means you don't have to fool with carburetor jetting, so you can focus on the ride.
This new frame incorporates a "Zero Weld" design for maximum strength. Both the main and sub frame are cast aluminum. The lower frame, which takes the majority of abuse from rocks and debris, is made of steel for maximum strength and durability. This new design also helps lower the center of gravity with engine placement as low as possible.
For ultimate track handling and stability, the YFZ450R is over 3-inches wider than the standard YFZ. The front A-arms now incorporate the "Wide Arc" design to greatly improve ground clearance, so obstacles are less likely to impact the lower a-arms. Upper and lower a-arm pivot points are now closer together to reduce the pivot angle and improve suspension control.
All-new suspension geometry allows for long travel front shocks with 9.8" of front suspension travel, that's 0.7 inches more than our standard YFZ. Brand new piggy-back reservoir front shocks are more robust with 44mm rods and a Kashima coating for reduced friction.
In the rear there's a new 15mm longer cast aluminum swing-arm with new linkage ratios serving up 11" of travel from a new long-travel fully-adjustable piggyback shock.
All three shocks (front and rear) have high and low compression, rebound and threaded pre-load adjustments enabling you to tune the ride to the conditions.
The new "wide-back" seat provides the perfect balance between comfort and movement. It's narrow in the front for easy transitions from side to side, but wide in the back to help cushion the landings and rough corners. And even though the YFZ R has longer suspension travel and a new seat design, seat height remains at a low 31.9".
A new thumb throttle design has an improved shape for reduced effort. The front flip-type parking brake is removable for racing. The front brake lever is adjustable and the clutch lever is adjustable on the fly.
Easily replaceable panels in high wear areas will provide flex and grip for aggressive riding.
20" rear tires offer the best all-round performance for track and trail.
65mm wide foot pegs help ensure your feet have traction when you need it. They are 20mm wider and 12mm longer than the standard YFZ.
LED tail light for improved visibility, longevity and reduced electric power consumption.
Wave rear brake rotor for less unsprung weight