There are honestly a LOT better choices than a dual exhaust. Look at the dyno tests in powertrain and those results will prove it. JSR, Jardine, Curtis sparks, GYT-R, LRD.. it all depends on what you want to gain and where. Also what type of riding you do. There are so many recommendations for exhausts based off of how and where you ride. I would do a little more research but if you absolutely have to have a dual exhaust... DON'T BUY LTE! Looney tuned Exhausts are garbage.
I know a guy who put on a LTE system on his YFZ and after 3 XC races it was freakin toast, he was Pi55ed because they are rather expensive. I would definatly do some research to be certain you get what you want.