are the ebay ones good?
Can I program them myself.
I bought my G35x with only one set of keys. I need to get a spare ASAP.
Any other place I can buy them besides the dealer?

also, what's the exact part number for the key?
I heard that ebay ones will work but they need to be the correct ones for the car. (06 G35x)

Dealer will have to program it.

this is assuming its the intelligent key..

the regular key can be programmed by an enduser

^^ what's the difference between the intelligent key and the regular key?

If you have the intelligent key you never have to take anything out of your pocket. Push botton to lock/unlock. Turn starter switch without puttin the key in, if you have the fob on your person.

Even the regular key with the transponder chip needs to be programmed. Either by a locksmith or the dealer. (they will need all keys though). The remote can be programmed by yourself. If you have the dealer do it, just have them do all of them at one time.

You can take a ebay key and have the dealer cut/program it. It's what I did for my 03 sedan.

You can't do it yourself? I mean program the actual Key?

I've owned cars in the past with chipped keys where if you had both, you could purchase a 3rd key, cut it and program it to the car yourself. The owners manual even explained how to do it.

If you only had 1 key, you had to go to the dealer though

When I bought my car (used) I got two remotes and only one actual key. I got a second key that fits inside the remote from ikeyless.com for $19.50. I took everything to a local locksmith that advertised programing serives. He cut the key and reprogramed everything for $75. I feel a little more secure knowing that not even the last owner has a key that works in MY car.