Originally Posted by 2011 Nismo#91

Budget:
Power Mods
1st Test pipes of your choice.
2nd Garageline X Mid pipe
3rd Axle back of your choice
4th K&N Drop in filters
This will give you the most bang for the buck.

Transmission:
0. Keep an eye one the color of your clutch fluid, if it goes to a dark black/brown change it. IMO RBF 600 or similar.
1. Save money for replacing your CSC with the Z1 CSC elimination kit.
2. Save money for upgrading your clutch flywheel
Buy/install them when your CSC fails or you have the money which ever comes first.
3. Low priority, LSD of your choice IMO Quafe, VLSD is only good for 30-50k miles and sucks for track type stuff.

Other stuff not really necessary
Sport brakes are very good.
For track replace pads and fluid, IMO Carbo tech XP10s front XP 8 Rear & RBF 600
SS lines are nice but not necessary, same goes for slotted rotors, Blank rotors are just fine.
Tires RE-11 are nice simmer tires, blizzak for winter tires on the cheapest rims you can find.
Oil cooler ~25 row is all you would need if you have temp issues.
Used Nismo coilover or KWV3s if you want to change it, V3s will be more comfortable.
Hotchkiss front swaybar and SPL endlinks.