I had the same problem with my 99' 450.
I got the Perfex long travel kit, that helped with tires rubbing.
I lost power too, so I put on a aftermarket pipe and clipped the carb spring. You should get a jet kit and a different air filter as well.
The pipes can get expensive but I found mine on another site, used for a good price. Up here in Canada, Pipes are from $400-$500 so looking around helps.
I got the Perfex long travel kit, that helped with tires rubbing.
I lost power too, so I put on a aftermarket pipe and clipped the carb spring. You should get a jet kit and a different air filter as well.
The pipes can get expensive but I found mine on another site, used for a good price. Up here in Canada, Pipes are from $400-$500 so looking around helps.