Facts, opinions?
http://www.vortex-performance.com.au/prod02.htm
it works now. Look at all of the features.

link no workey for me

A LOT OF MONEY FOR NOT MUCH HORSE POWER.YOU WILL GET A BETTER GAIN BUY CHANGING OUT THE CARB. iF YOU WANT MORE RPM i KNOW A GUY IN OREGON THAT CAN INTERFACE A DRZ 400 ELECTRIC START CDI BOX THAT WILL GIVE YOU 11,500 OUT OF THAT MOTOR BUT YOU WILL NOT GAIN MUCH HORSE POWER AFTER 6500 INLESS YOU DUMP MONEY IN TO A BIG BORE KIT LIKE THE YOSH 450 KIT. THE CARB WILL GIVE YOU BETTER THROTTLE RESPONCE AND ADD ABOUT 2 HORSE POWER ACROSS THE BOARD.

I would get this in conjunction with stage 2 hotcams, drze valve springs, and a header for my HMF.

IF YOU ARE GOING TO CHANGE THE CAMS YOU MIGHT AS WELL LOOK AT ALBA HAS A KIT FOR 524.00 IT INCLUDES A J E HIGH COMPRESSION PISTON WICH YOU CAN USE PUMP GAS ANT IT COMES WITH BOTH CAMS AND GASKITS.yOU CAN THKE YOUR HEAD IN AND HAVE THE CAMS CHANGED AND THET CAN ADJUST THE VALVES IT WILL BE LESS HEADACE THEN THEY WILL GIVE YOUR HEAD BACK READY TO GO BACK TOGEATHER.ALBA CLAIMS IT WILL GIVE YOU 40 H.P MIGHT BE WORTH LOOKING IN TO.CALL ALBA FOR INFO

Remember you will have to get stiffer springs for the valves if ya get cams, people have been using drz vlave springs, they are a little stiffer

Thats too expensive, Im just doin stage 2 hot cams, drze valve springs, and a vortex cdi. Im having it installed, so I dont want to pay an extra 300$ in installation and sacrifice reliability with a piston and gaskets.
Other thoughts about the vortex, what kind of power increase am I looking at w/ the most agressive curve.

I don't think that vortex box is worth the money inless you build your motor the z-400 signs off the horse power curve at about 6500 and then you just over rev the motor and loose horse power on the back side of the curve I would buy the alba box that will give you 1000 more rpm to go with that cam set up.I have went over this and have talked to several shops and the rev box is pretty useless in less you are willing to go with a big bore kit. Here is what I did I looked at the cost of getting more horsepower out of my bike it would cost about $1200 to $1400 just to start then you will have to upgrade the suspenision at $1600to $2500 so I did the math 03 z 400 worth $4500 cost of all the mods $2500 to $4500 Cost of yamaha yfz450 $6899 cost of Honda TRX 450R $6400 so sold the Z-400 and bought the Honda TRX 450R and the Z-400 can't even touch the 450 class out of the box so the bottom line is you will be money a haed by selling the Z and buying power right out of the box. The power difference between the z and the trx 450 is like riding a Honda 300ex then going up to the z-400.The power out of the box on one of the 450 bikes is amazing. After riding my trx 450 then going back to the z it felt like a snail.

Ive also been looking at a yfz or a 450sx too.

just think it over before you dump thousands of dollars in that bike and still be sorry that you did'nt step up and buy a 450.I was in your shoes a month ago. I mainly ride sand on the oregon dunes.I took my z to the dirt and the power was totally diffrent.I found my self hanging on to the z but if you do mainly sand it is a little under powered and you will spend thousands of dollars on the z to get 450 type power out of it. The cost diffrence is not much concedering that you will spend
that much on pipe and a few other mods and wont even come close to the 450s good luck my z was a fun bike and bullet proof in the stock or with a few mods but start going overboard and reliability will suffer and no one wants a broken bike while on vacation