Buying from the builder Directly vs with an Agent

[Sudeep Mathew]

Wanted to understand on how using realtors with National builders work.  Does the builders typically have additional negotiation room ( the commission they would have otherwise paid the realtor), if a buyer directly approach the builder. ? For the realtor to make sense in new home purchases, they will have to negotiate discounts over and above the 3% commission amount that builder pays the agent for the buyer to see some price benefit. Any additional information on how this works would be helpful. Also is it better to use the builders loan officer or go with pre approved loan when going to a builder to buy the home?