Kl-ze

i need to know if i have to use the KL-ZE ecu with the KL-ZE engine and if i do do i have to use the KL-ZE vane airflow sensor?

you don't "have" to use the ze ecu (kl31 and kl36) but it's a good idea..You'll improve performance and gas mileage..If yoi keep the k8 ecu then you'll also have different VRIS point affecting your performance as well...the vaf sensor for the ze is the same as the mx3..same part number ..JE-50..i hope this answer your question

do i need the vane airflow sensor for the engine?

what is vris point?

if you own a mx3 your stock vaf is the same as the klze so you keep the stock one...
vris means variable resonance induction system
it's in the intake manifold...the air takes different route in the intake manifold with vris open and close they are optimized for having more hp....so if you use a different ecu with a different intake manifold your vris point (different rpms) will be different so you have the "perfect" combo..it's hard to explain