As I too work in the automotive industry (I write the software that some of the dealerships use on the front end, desking, and F&I) there is one crucial part that is left out here, the dealer in like 98% of the cases makes money, lots of money, on the loan itself, as the dealer has a better credit rating than you, say you got a 60 month loan at 5.9% APR, well the dealer gets the same loan at say 2.4% so they are skimming 3.5% off the top and keeping it for themselves...
there is a lot of money in the automotive industry, and it is the most cut throat industry in the world.... but dealers selling for invoice is no skin off their nose, and then every dealer is different, typically the larger dealers, sell for 500-1000 over invoice, and are easily talked down to invoice or a small bit above, it is the small dealerships that fight for every penny and are less willing to deal, also if the car/truck/SUV is hot, they will charge through the nose, look at the PT cruiser when it came out you were lucky to find one that was under 35000, now they are dirt cheep, same went for the neon srt-4 the 300 z, the thunderbird.... etc..... etc....
now most of the above listed are hard to sell, (cept the 300z
), and you can pick up for bargain basement prices...
just my point of view, and it is a fairly wide one, as I have everything from KIA to Ferrari dealers (mostly benzo)...