The Costco program varies by vehicle and to a certain extent, by dealer. If you qualify for VPP through your employer, that's a better deal. But the Costco program should generally get you a very good price on the car without having to do a lot of haggling. Could you maybe negotiate a better deal on your own? Maybe. Do you want to deal with the hassle? That's up to you. At least at our dealership, the Costco deal is a pretty good one. If you're in the Bay Area and want to take advantage of it (or just get a great deal in general), feel free to contact me.
It must depend on the make and model because we bought our 16 yr old daughter a 2012 Honda AWD CRV through the Costco program and got it a little below invoice from a dealer in Chicago. No other dealer in the area came close. We picked it up the same day I took delivery of my JX since both dealerships were in the city and we live in the Northern suburbs.
There seems to be a lull in JX sales from what I have seen (around here, anyway), my dealer currently has 25 on the lot and more on the way. I counted around 30 at one SoCal dealer. Before you drive around to all the dealers, look at the Infiniti website where the on-site inventory is listed. Then go to your dealer of choice with the position that you are there to help by taking one off his hands and reducing his flooring costs, because you know how many are around.
We ordered our JX from and then later cancelled due to price increases an schedule issues they created. A few months later, when they had 28 on the lot, the salesman texted me about coming in for a second look. By then we had our Pathfinder on the way, and I had learned too much about its new transmission and drive modes, so we passed on the second round of negotiations, no matter what the price reduction on a JX would have been. Moral to the story? It's a buyer's market.
Don't bother with Costco program with JX. You should easily get this below INVOICE. Read Edmund's discussion thread. Many people getting that type of pricing. I think Pathfinder is eating into JX sales.
For what its worth. Made a purchase in Northern Calif. at the end of Dec and payed $1k below invoice with all weather floor mats and mud flaps thrown in. I think it was a fair offer and that included them going to the bay area to get the one I wanted.