I noted that another poster argued that this was $500 too much.We are paying $500 over invoice, $39,718.83, for our RTL-E through Costco's auto buying program, which uses Costco-negotiated preset pricing.
I don't know what RTL-E's are selling for in your area right now, but like all new vehicles (and for that matter homes), the real value is a function of what people are willing to pay for it at the time you buy. It may very well be that these vehicles are typically selling for $1,000 over invoice in your area right now. I don't know.
Having used the Costco service for my G1 purchase, I'm intrigued that they will offer to negotiate in cases where the vehicles go for a premium over invoice. In my case, I didn't use the Costco buying service in the end, but used it to negotiate a deal (that I thought was a little better when my trade-in was included - hard to know for sure) elsewhere. But with the apparent shortage of new RTL-E's out there and the litany of outstanding reviews, $500 over invoice may be a great deal in some areas. I don't know.
I also agree with your point in a post below that your time is valuable and spending lots of time on negotiations may, in the end, cost you.