first of all, the 2003 350z has aps twin turbo with 91k on it and now I'm dealing with the overheating problem maybe some of you guys could help me here, when the overheating started I began to flush out the coolant, still OH then I began to replace the thermostat, still OH and I tried doing the blur (leaving out the rad cap) but all it does it spill out coolant, btw there no heat from the cabin. any suggestion would be greatly appreciated.

Hopefully the head gasket isn't blown away.

 

^^ You are experiencing a known problem with the Z. You have air in the cooling lines. The fix is expelling this air. A search shows how you do this and solve the problem.

--Spike

 

^^ Spike's right, you could search under "Burp". Good thread there, as I just lost heat in my Roadster, but no overtemp.
When the car is cool, fill radiator and overflow to limit. FIND the bleed screw for the heater core. Small, black, just beside the battery cover. Open, and with a funnel fill with coolant till full. Replace screw after filling, and drive.
You may need to repeat this process several times, my car required two cycles.
Good Luck!