2mm will make the different already. More air to go in to the air chamber and combusion room. That's why some bore it until 64 or 67mm... After market TB like Jun is 70mm at inner diameter. But bigger doesn't mean better, big enough for ur engine OK lar. Don't tell me a stock b16a is going to put a 67mm or 70mm TB.
y our z club don have personal number or sticker(logo) like caldina club ahhhhhhhh
if have next time when we saw z on the road we can know tis is member or musuh maaaaa
if member we can sayhalo loo but musuh we can...