For anyone reading this at the present time (2015), having gone through this myself, my agent was useless for negotiating with the builder, as it has most of the leverage. Your best bet is to figure out what items you want in the new build, hire an appraiser to figure out what comparables in the local area are selling for, then hire a lawyer to negotiate the purchase contract for you. The contract the builder will give you is skewed towards them on all things. I had an attorney relative review the contract for me ahead of time and I pointed out all the things to the builder's rep at the meeting. She basically said weren't not changing the contract and you can go buy from someone else. I think if you have an attorney negotiate for you, they would be better able to tell them what the law actually is. Good luck!