Your mortage lender will likely find the 5 BR plan to be "worth" lending the extra amount. They won't be at all keen on lending money for "upgrades" that do not add square footage and do not add any real bump in value for an appraisal. The appraisals for loans are based off of what the bank could sell the house for if you went into default, not what it cost to build the house. If your plan is to upgrade the finishes the same dollar amount as the extra square footage would cost, expect those upgrades to come entirely out of your pocket, not the loan. And, still expect to bring money to the table to close the loan with. Very very few homes are appraising at the build cost. Most people are having to bring a big chunk of change to closing, and that's without upgrades above base. Right now, the per square foot to build cannot approach the low square footage cost to buy existing. Custom homes are in the $150-$200 a square foot range, while existing homes are half of that. If you want your money to go "further", then buy existing and give building a wide berth. It's only for those who have very special requirements that cannot be easily met with the existing inventory.

I could be wrong, but based on what I've seen, a solid dark granite will be much more durable than quartz. I was able to scratch the heck out of engineered quartz (with a knife), nothing but a hammer had an effect on the granite. With the hammer, the quartz was demolished, the granite had a mark. I'm sure I could have broken it if I hit it a few more times. The thing is, there are many kinds of granite, and some of them are much more brittle than others. The ones that are durable seem almost indestructible. I'm not sure that has any connection to the price either. I bet you can find granite that is both cheaper and more durable than any quartz on the market.

I think it would be a bad idea to turn an entry door into a Murphy door. You'd hate it every time you had to walk through it and deal with the bulkier door. And I assume it would be in-swing, with the closet part on the back? So you'd have to close the door to access the clothes. I think the point of a Murphy door is to hide contents within the walls. This wouldn't do that. If it is something that would provide value to you, then consider doing it. Don't do it in anticipation of selling the house for a higher price. That's my general advice for upgrading a house. Don't do things you won't use/enjoy just for future buyers. And don't not do things that will help you enjoy the house just because a future buyer won't likely pay for it. The main things to ask the "resale value" question on are things that might devalue the house. Try to avoid those.

qam999, I just looked up market info for my first house. It was in Sunnyvale, about a 5 minute or less walk north of Apple's flying saucer. Like much of Sunnyvale, it's in a neighborhood of tract houses from the late 50s-early 60s. 1300 sq feet, 3 bedroom, 2 bath, on a lot of 6500 sq feet. The Zillow estimate is $2.1 million. There are some slightly larger houses on the street, some 4 bedroom, they're more expensive. Master suite? Ha, I recall the bedrooms were 12x12 at best or less. Owners of such places wanting more space sometimes build a second floor for a master bedroom or family room over the attached garage. Or, convert the garage to living space. Of course there are a lot of multigenerational families in the area, typically folks who are Asian immigrants to Silicon Valley. A lot of the existing housing stock, is small in size. The older tract neighborhoods and other places are like that, with older homes (I'm thinking like the Rose Garden or Willow Glen in SJ). Like much of Sunnyvale, they don't easily accommodate middle class extended families needing many bedrooms but the houses have no problem maintaining ever-skyrocketing values because of their close-in locations. In those areas, with older homes, often the only solution is to add space or knock down and rebuild but many families may want to find something ready for move-in. And lots are often small. As you know, many such families are in places like the Fremont area, etc., where the housing tracts homes are newer and larger. In the older areas, where lot space allows, some build granny flats. The Bay Area is quite different from other places, different from even other parts of California.