I don't know about invoice, but I got my White Platinum Tricoat with Recaro package and navigation (no sunroof or stripes, etc) for around 23K before taxes through Military Auto Sales. They are usually similar to Truecar or USAA pricing, but the benefit for me is that I don't need to get that price on a car on the lot... I was able to purchase the car with those incentives. Additionally, if any better incentives are offered I receive them. However, I doubt anything will be coming out on 2016 models over $1000 bonus cash and/or good financing on a model you still can't get off the lot!
I believe I received my VIN for mine ordered in late July on 27 August 2015. I've been quoted 2 months build time, so hoping by 27 October, but dealer estimate is sometime in December. I think the latter estimate is a CYA estimate.