Lexington MA plot of land - teardown worth it?

[Drew Slew]

Quick question for people familiar w Boston and Lexington real estate in particular. Have a plot of land that has a house on it, around 800k range, but would want to tear it down and build a new construction to make a few hundred K profit (as many do in this suburb). Not entirely sure if its a good investment or not. 

House as it would be around 4000 for mortgage+tax, and max rent it could fetch is 3000 or so in the meantime we'd prepare to get plans, constructors etc together to build a new house on its plot. 

Not sure how much tear down is, how much a decent new house build cost is, what hoops and cavaets and hiccups occur when a rookie is building a brand new home from top to bottom, without an established constructor crew. We'd estimate around 2yrs to get all of it done and sell place for 1.5-2M. 

People say this suburb is one of the highest priced around boston, holds value prices well and new construction and even land is very hard to come by here. 20mins from downtown boston. 

Happy to hear thoughts.