What should I accually pay for aG35 Infinity 4 door sesan

Go to Edmunds.com and look up the TMV (True Market Value) for the car you want. This is the price that other people are paying for that car.

I think you'll find that Infiniti cars aren't discounted the way a Ford or Chevy might be. Infiniti wants to be known as a luxury car company, not a discounter. They don't have to bargain because they have other customers who will gladly pay full price.

If you give them the invoice price they should kiss any spot you specify - infinity is not exactly the hottest brand on the block.
You can find invoice prices on Yahoo autos.

Imports have less markup then domestic and new cars have less markup then used. If you are in a cold climate buy a two wheel drive G35 in the winter and get at least 2k off. If you are in a warm climate look at 1k-1500 off. If it is a new body style that just came out look at 200-1000 off this is the best time to buy the left over old body style and look for 2-4k off.