ive heard differnet with the sparks pipe.. from aussiequadrider and a few poeple on yfxcentral.com

 

I noticed the most improvement from stock with the GYT-R full system in the low and mid range.. VERY dramatic results to an allready nice quad.




http://dirtrider.com/tests/141_0303_pip/

check out this test of full exhaust systems on the YZ450F dirt bike .. should be very representative of those production pipes out for the YFZ 450.

 

go with the lrd

 

I have a GYTR and it's been an awesome pipe. I raced other YFZ's at Dumont and beat every YFZ I raced. Of course that's not everything but it made me feel more confident in Yamaha engineering.

But, as with any pipe discussion, you'll get 10 different pipe opinions. It's almost like asking how much HP a quad has... For the most part, they will all be close.