I just bought a 98 Cat ZR600 EFI LE the other day and today we got about 4" of powder. I decided I couldn't wait for more snow so I took it out for a ride to a local school to see what it could do in their field. (Don't worry. Schools were closed today for the holiday. I wasn't gonna run over any 8 year olds.) But anyway... The only thing I have done to the sled since I brought it home was "attempt" to fix a leaky water pump housing. Other than that I have not done any work to it. I'm not sure if it is a problem or not, but something is tellin me that it should top out a little faster than 75MPH wide open. Keep in mind that it is clutched and chipped, plus an aftermarket silencer. It didn't seem like it was bogged down or anything. It actually sounded like it was running pretty well. Again, I'm not sure if it is a problem with the sled, lack of snow, or something else. Maybe there is nothing wrong and I just anticipated more from a 600 EFI. Anyway... if anyone has any ideas, please let me know.