I'm looking at getting a left over 2009 YZF 450 or 2009 KX450F. I can get the YZ for a really good price but have been doing a lot of research about all the 2009's and currently ride a KX250F and YZ250 for moto mostly. I read that the YZF 450 is a pretty good all around bike but that it's slow with the stock exhaust. I've also read that with an aftermarket pipe, the engine really comes to life, is this the case? If this is true, what pipe have you guys and gals been getting the best performance out of, DR. D, FMF, other? Also, does anyone use a DR. D radiator lowering kit or offset triple clamps to help with turning? I like Yamahas and have had a few, they are durable as all hell and are for the most part good bikes, though the best bike I've ever had is my KX250f. That bike is awesome. Thanks.