The issue of the difference in price is one of cost vs market forces.
I would suggets that the Salsa Eos is being advertised at close to list as the dealer has only just got it and is hoping for a keen buyer who wants a red one.
The dealer with Opal Silver Eos has possibly had it for a while and wants to clear it.
First thing I would do is to get onto the VW website and get the list prices for both vehicles, complete with any extras they have.
Take a look at what ever discount is being offered off list for the Opal Silver one, and you know how much a dealer has to play with as a minimum - odds are you could screw the dear with the opal silver one for a bit more.
Go and see the guy with the Salsa car, tell him up front you know how much he has to play with, take that discount off the Salsa cars price and offer it to him, telling him if he'll do the deal you'll buy now. ( if you are confident, off him a few hundred less)
Dealers will only talk absolute bottom line if you are ready to deal on the spot. It does cost them money to keep a vehicle they already have on the lot, and they will often conclude that money in the bank now is better than the possibility of more money in 1 or 2 months time.
Be prepared to walk if he won't do the deal, but offer to call back next week and see if he has changed his mind, reminding him that there are others you are looking at.