Does not exist in the US. They have some basic items in Japan, but they are very expensive.
You can piece parts together here, but for most of the things, you can probably go better aftermarket.
Dissecting a 2012 GT-R .
http://www.2009gtr.c...issan-gt-r.html
Nicks list of parts
http://www.2009gtr.c...-gt-r-with.html
Black Edition US Wheels

10 Spoke wheels:
(front) D0C00-KB50A =$1,950.98
(rear) D0C00-KB51A=$2,010.85
"BLACK EDITION" WHEELS
(front)D0300-KB60A MSRP=$2,406.16 EACH
(rear) D0300-KB61A MSRP=$2,463.46 EACH
DBA Front bumper (does not include running lights):
FBM22-KB60H- Front bumper fascia - Unpainted=$1,483.45
75830-KB50A Front lip spoiler (cover-engine under)=$1,720.34


DBA rear bumper valence:
HEM14-KB54H - Bumper - Rear, Center valence=$635.97
748A0-KB51A - Diffuser rear=NO PRICE AVAILABLE AT THIS TIME
Suspension components :
54500-KB50A Front control arm RH=$758.32
54501-KB50A Front control arm LH =$758.32
CF Strut bar:
bar assy - tower: 544A2-KB50A=$1,874.00
tower bracket LH: 544A
6-KB50A=$21.37
tower bracket RH: 544A7-KB50A=$21.37
bracket bolts: 673N8-JF00A (x2)=$5.60(X2)

2012 damper and spring part numbers/MSRP
Front right damper: E6110-KB50A=$1,733.31
Front left damper: E6111-KB50A=$1,733.31
Rear damper: E6210-KB50A=$1,733.31 (x2)
Front spring: 54010-KB50A=$350.05(x2)
Rear
spring:55202-KB50A=$502.59 
2012 Nissan GT-R wheels
Front suspension/calipers.
The front upright is the same.The hub is different part (new # 40202-KB50A).
Caliper appears to be a different part # (41011-KB50A), the Spec V caliper is different as well from previous Spec V (41011-KB60A)
FRONT CALIPER SPRING PART#41090-JF20B MSRP=$7.62 EACH
Right side turbo
Part # 14411-KB50A MSRP $2,209.20
Left side turbo
Part # 14411-KB60A MSRP $2,209.20
Right side intake suction pipe
Part # 14460-KB50A MSRP $265.92
Left side intake suction pipe
Part # 14460-KB50B MSRP $265.92
CBA-R35 Turbos, RH, LH
Early My2009 USDM, 2008 JDM, 14411-JF03A & 14411-JF03B
Late My2009 (+ Euro models) and My2010-2011 14411-JF10A & 14411-JF20A
2010-2011 SpecV 14411-JF30A & 14411-JF40A
DBA-R35
My2012 14411-KB50A & 14411-KB60A
Cabin Vents: 68755-KB50A (need 4)
Cluster Lid (CD slot):
68259-KB51A Pure Edition (Base Audio, not Bose?)
68259-KB51B Premium Edition
Climate Control / Radio Panel: 25391-JF33A
Interior grab handle (part # 80944-KB50A/80945-KB50A) MSRP $250.43 EACH
Interior door handle (part # 80670-KB50A/80671-KB50A) MSRP $81.47 EACH
Rear cup holder (part # 96965-KB50A) MSRP $44.98
Front cup holder trim (part # 68961-KB50A) MSRP $73.90
Center console finisher (part # 96941-KB51A) MSRP $419.81
Left side center garnish (part # 68311-KB51A) MSRP $109.22
Right side center garnish (part # 63810-KB51A) MSRP $109.22
Center mask (part # 68312-KB51A) no price available at this time
Cluster lid(CD slot)
(Base audio, not Bose)Part # 68259-KB51A No price available at this time
(Premium edition) 68259-KB51B MSRP $130.98 Not sure if it is carbon for this price? Seems kind of low for a carbon part, About the same price as the 2009-2011
Cabin vents (68755-KB50A) MSRP $127.85 EACH
Climate control/radio panel (253914-JF33A) MSRP $1,240.26
Shift knob (34910-KB50A) MSRP $327.87
thermostat housing is 21200-KB50A. MSRP $ 65.50