What are the benefits of fitting the XEV cams to the Zlet engine?
What is the pwr increase?
power increase, i'm not sure about, torque increase is a defo IMO but i don't know by how much, drivability is good, responsiveness is also good.
not much help i know, sorry.
There should be difference in high revs! No or little in low revs... NO change in drivability and responce.
The only way to be 100% certain that work has been done properly is to do it yourself.