It says it's for your model plus you get the spring and some weights to help tune.
I think he was refering to the performance was dead because not all was matched and tuned. It can get a little tricky your first go around.
For example if you just do a spring change your weights may no longer work well at that rpm for you.
But malossi usually puts a good kit together for ya out of the box,and should put you in the ball park right off the bat.
The more you know your bike the easier it is to decide what works best for you then you can fine tune even more from there with fly spring belt and what not. It's a bit of trial and error but good expierence all around.