"Off invoice" is a very slippery term for dealers, especially if their so-called invoice includes garbage fees, dealer-added "options" like undercoating, pinstriping, etc.
for pricing on the Eos - you'll get a breakdown for the actual dealer invoice (what the dealer pays VW) for the car and legitimate options, retail price, and the "True Market Value", which is what folks in your zip code are typically paying. I'd be really surprised if the dealer is truly offering you $4K off his invoice, especially on a car he doesn't have on the lot.
Edmunds also lists current manufacture incentives. Right now I don't see any $4K manufacturer incentive listed. There's a $750 lease rebate, low financing rates, and $2K manufacturer cash to the dealer.
I found when buying our Eos it was best to talk total out the door
price with dealers, including the VW destination fee, any dealer admin fees, taxes and tags. There really aren't too many options available on the Eos, so it's easy to compare between dealers. A dealer may try to lure you in with an artificially low price, intending on having his closer make it up by selling you additional stuff you don't need or want.