As much money as they charge for those upgrades, I’d seriously consider making a deal for a house with no flooring or cabinetry and do the interior myself. Pay the base price as if it had the standard buildout; get a credit for the itemized total of the “standard” cabinetry, fixtures, appliances and flooring; and then hire an outside contractor to finish the interior to your specs. You could probably parlay an accurate credit into a very nice interior buildout and save yourself an easy $50,000 or more. And it would still be financed in with the base price.
One more thing to keep in mind – it’s highly likely that the differences in builder upgrades for these homes will become basically invisible in the resale market 5 years from now. Friends don’t let friends get carried away at a developer’s design center.