Upgrades, interest rate buydown, closing costs, etc , don't show up in public sales price or what has to be reported to the bank. I hope this helps.
It will be much easier for the builder to give you upgrades instead of money.
If you are not already beign represented by a realtor, please call me and I'll be gladd to help you in your negotiations.
It is always easier to negotiate for upgrades rather than dollars. The reason being that upgrades have profits built into them. The buyers purchases the upgrade (counter top, fridge, etc...) at cost and sells it to you at retail. So each dollar in upgrades costs the builder an amount less than a dollar. Also, if the home is in a development, the builder usually prefers to give incentives rather than lower the price as lower prices often anger buyers who have already purchased in the same development.