I have a 2003 350z and i lost my only key recently and i was wondering what my options are? can the dealer cut a new key just by knowing the vin

 

Most of them can do that. Look in the owners manual to see if someone wrote down the key code.

You will have to have proof of ownership either way.

 

I recently lost (1) of my keys along with (1) of my key fobs while canoeing, it's a funny story but I had a locksmith meet me at the car, he made a new key on the spot for $170, the problem with that is my other key no longer worked, when they program a new key any other keys become disabled, I had Nissan make me another factory key as well as reprogram my other key and give me a new fob, with labor I paid nearly $300.

 

What sucks is they literally just put some info into the computer and takes like 10-15 minutes. They really get you on the key thing. My friend who worked at a Nissan dealership told me this.

 

Yeah they do, the locksmith who came out literally just put some information into his smartphone in order to program the key.
It turned out to a very expensive canoe trip, $170 for a key made on the spot by the locksmith, $200 for a lost iPhone(girlfriend's) and then $300 for a factory key, fob and reprogramming the other key.
It was an expensive lesson to learn not to stand up in a canoe and take a ****.

 

so if i have a lock smith come and make the key will that key be able to start my z? or do i have to take the key to the dealer to get it programmed to start the car? or does the car have to be at the dealer?

 

That key will be able to start your car, the locksmith will make and program it on the spot, do some research, find the locksmith that can do this that is the closest to you, I paid a lot of money because I didn't do that, I chose a locksmith that was 50+ miles away and it cost me extra for him to come out.