I did it! 13 yeas of riding KTM’s and I thought it was time for a change! Selling my 2000 520EXC, which I love!!!!! and bought a new WR450F. I have struggled with the Yamaha
for approx 250 miles. Only starting to get a feel for the bike. Switch with my KTM friends for a while and I feel right at home on the KTM. Something about the feel and handling. Anyway, as far as the power, I am 6’1” 200pounds and the 520 always put a smile :Don my face while riding. I switched to the 450 because of all the talk about how much easier the 450 was in the woods. I have not found this to really be true!
The difference is so slight; I would prefer the additional power of the 520. Find someone with a new 450 and ride it long enough to form your own decision.