he does not have twin throttle bodies, he has the VQ35DE with a ingle throttle body on the driver’s side. the 07-08 350Z’s have the VQ35HR motor with a whole new plenum and a throttle body on each side.
and for the HR, unless you have cams, a built block and a full 3 or 3.5" single exhaust, the stock airbox with a K&N filter is the best setup. you’ll gain <3whp from a Nismo or AEM or whatever CAI setup and the heatsoak drives people crazy.
OP, nice pick-up! let me know if you need anything, like any questions about the motor, detailing, whatever. i’ve got the same motor, just with a different IM and mounted the wrong way :facepalm