There are too many variables for a specific answer. It depends on what year of a Z400 you are speaking about because there are differences between the early years and the middle years and the current years of the Z400. The LTR450 was basically the same from conception to its end in 2009 with a few engine upgrades in the 2008 and 2009 model. Basically, to answer your question at its simplest, the Z400 is a great all around quad for recreational riders. The better years are 2005 and up; the 2009+ years now have fuel injection. The 450 is more of a race style bike and is designed to suit motocross or more aggressive riders.