you guys know which part of my ltz 400 I should get for increase my Hp/CC which one wont broke every months hehe Please just tell me how I should modificatemy LTZ 400 pleas thank before-

 

going to need more info , what year is your Z,what have you done so fare, how much money do you have to spend?

 

2007 bis the yesarsand about 3000buck i got in my bank i Can spend ;]

 

the simple stuff is a pipe ,Yoshimura works well on a Z ,so does HMF. your going to want to get the full system pipe header and silencer, either setup will come with jets.
you will have to rejet. remove the air box lid , get either a UNI air filter or a K&N ,a dynojet needle , and a dynotek cdi. all these things are the simple bolt on items......thats about a $1000. dollars worth of stuff . happy hunting