I've got a 2005 model z400.
I'm going to put a new pipe on it, but i'm just going for the slip-on exhaust.

Narrowed the choice down to the FMF powercore, HMF , and the procircuit.
I really don't know which one to get.

please can i get some of your thoughts on this.

 

If I were you I would go with the hmf or yoshi since they are you best choices for the z400 and I would get yourself a good jet kit for it...why not just save up the extra money and buy a full exhaust its well worth it and you have to rejet either way

 

I would go with the yoshi full system if you want the most bang for your buck. I went with a hmf slip on and i think the only difference on my quad is that its 50x's louder.

 

save your money and go full exhaust, you wont regret it

 

Look at this link at decide for yourself.
http://www.ctracing.com/ltz400%20pip...t%20mag%20.htm
It's an article taken from dirt wheels magazine march 2003 on different pipes for the kfx/z400. Though it's 3 years old, it should still be very applicable. After reading that, I decided on the HMF pipe. Ebay sells it for only $449 for the COMPLETE exhaust system with jet kit and foam filer. http://cgi.ebay.com/ebaymotors/ws/eB...5868499&rd=1,1

 

ya DON'T waste your money on a slip on ...

 

Dunno,

I lot of the guys I ride with who went with full systems ended up putting the stock header back on.

They claimed the only ain was on top and that did not help much in the woods and tight stuff. Guess it all depends on what gain you are looking for.

 

Look into the Dr. D. I installed on with a dyno-jet kit and jetted w/o the air box lid and it's running great. The sound level isn't overly loud but dang does she sound nice. If you haven't modded the air filter and go with the lid you shouldn't even have to jet it (according to thier site). I know you didn't mention them but figured i might as well throw it out there. and i agree the full system isn't worth the extra $ espcially since it was $300 for the jet-kit and exhaust. Doesn't get much better then that i believe....

 

Go with Yoshi Full System

 

out of the ones you said i would get the hmf slip on because it sounds nice and gives some power. but if u want my honest opinion of all slip ons for the z i would get a two brothers because they are a little quieter than the hmf and all the power is in the bottom and mid so its perfect for trails.....just my $.02