Go to
www.edmunds.com and build your Tundra exactly how you want it. They will tell you what the MSRP and invoice prices are, as well as how much others in your area are paying for the same set up. If you are in a high-volume area, I wouldn't give the dealer any more than $1K over invoice. If they want more, tell them politely that you'll go to another Toyota dealer that will accomodate your price. When you pick up the keys to walk out, they'll cave and you'll get your way. It's worked for me with both of my Toyota's (2006 RAV4 Sport and 2007 Tundra TRD DC). Be sure to come back and post your results here! Good luck!