IOW, only works if dealer is honest.
VW has 2 dealers in my region. Want a TDI Jetta with a manual transmission? Let the games begin -- they get 3 a month and the sales manager won't let it out the door for a good price.
Toyota used to have supply constraints for certain Camry models (some trims were made in Japan exclusively a few years ago). Want one of those? Good luck -- my dad had the guy demand a deposit to be on a waiting list, or take a lousy deal on one of the other trims.
Another thing that happens is that dealers need to trade with other dealers for specific cars. Sometimes these deals fall through, and the dealer who promised you a car is actually being honest -- he doesn't have it for reasons out of his control.
Interesting note: Be very careful about believing a dealer's website or phone description of a car as a "manual." We ran into multiple dealerships that misidentified paddle shift or "manumatic"/"tiptronic" cars as manuals.
He ended up with an RX-8, but that's an entirely different set of stories... :)
If the supply of a certain good is constrained, then obviously the value goes up. Simply being able to purchase one is a good price by definition.
The only correct response to such a situation is: "I will tell everyone I know about your tactics, and go with the dealer that was shooting straight."
Then execute on exactly that plan.
VINs can be decoded to exact colors/features for most makes/models.
In other words, go to another dealer.
Also, an interesting aside, there's a limited inventory in any given geographic region, so if you match your desire list up with a given VIN, they're usually quoting you on the same inventory item.
As others have said, this doesn't work for all cars. For less mainstream / luxur-ish cars, there won't be too many dealerships in 100 mi radius that carry what you want. At best you'd get a response that MSRP is this and that, please come in and we'll talk about discounts.
I think that's their idea of a hint.
In fact, I praised her more than the agent I got my flat through, and it's her who gets my recommendation whenever someone asks me.
I offered the local dealers the chance to match the price, but after hearing the figure I'd been quoted, they politely declined. They claimed that they would actually lose money on the sale if they did, and while I'm not an expert on the UK new car market, I suspect given the size of the discount that the local guys were being honest there.
Caution: That was mid-2000s, so any recommendation for that particular deal site is stale. Still, I have no reason to believe they have changed and apparently they're still going.
Do you sell it yourself?
Why? Because in the used car supply chain, the trade-in is the start of the chain - the lowest possible price, and the worse possible deal.
The supply chain (in its longest form) looks like this: Used car retailer sells a car (end of chain). He buys the car from a wholesaler. Wholesaler buys a car from an auction. Auction gets its supplies from dealerships. And what cars are dealerships putting in the auctions? Trade-ins.
Now, that chain can be broken at any time -- that's just the longest version. But dealers calculate trade-in prices with the assumption of a worst-case scenario (that they won't be able to sell on the lot and that they'll have to dump it to an auction).
So moral of the story - if you have the time and know-how to sell direct, do it!
Step 1: Decide what car(s) you want to buy, down to the color, trim, options, etc. Type it all out in concise list form.
Step 2: Visit Edmunds.com, etc and get a general idea of local fees, taxes, and costs.
Step 3: Find the dealer websites within 120 miles or so, and write down their "Internet Sales" and "Fleet Sales Manager" email addresses.
Step 4: Compose an email to each of the email addresses you wrote down. Say that you are sending this out to several dealers within 120 miles and you will be selecting the lowest cost for the following list (which you created in step 1). Ask them to give you their "walk out the door" price. This price will include all fees, taxes, costs, etc.
Step 5: Wait. Maybe 30% of them won't reply, but that's OK.
Step 6: Take the lowest quote and tack it to the wall. Send another email to the next 2 or 3 lowest quotes saying that the guy tacked to the wall is quoting you $true_value (don't lie). See if they come down in price.
Step 7: Pick the one.
This has worked 3 times for buying a new car. No haggling or even stepping into the car lot until negotiations are done. You don't necessarily have to take the lowest quote (it's nice to pay a little more for a dealer closer to home) but it sure does drive the price down.