with the skunk2 manifold, is it better to get the Type R throttle body as well or just stick with the GSR's and make the necessary adjustments?

btw: just how much does the Type R throttle body cost?

 

I've got a JDM B18C1 with the following mods

JDM Type R cams
Toda Cam gears
VAFC
Lightened Flywheel
LSD
AEM FPR (A/F meter)

I'm planning on the following mods,

re-chipped ecu JDM Type R specs
JDM 4-1 headers
AEM CAI
Skunk2 manifold

is there anything I should need, or am missing out?

 

With your mods I rekon you'll benefit a lot from a larger TB.
Just getting your one bored out to aroung 62-64 mm would cost heaps less than a type R.