Until the end of the year Fannie Mae limits have been raised from $417K to custom levels by MSA.  Hawaii still has the top limit of around $793K with a number of major metropolitan areas in the $729K arena.

Go to https://entp.hud.gov/idapp/html/hicostlook.cfm to look up an areas new limits.

Calculated Risk has a nice summary of the new underwriting guidelines.

The goal is to make mortgages more affordable in high cost metropolitan areas and it will likely do that.  Unfortunately, this will probably have a side effect of making small mortgages more expensive.  Because large mortgages are riskier, including them in a mortgage pool with the smaller mortgages, means the overall risk of the pool goes up and therefore the risk premium demanded by investors goes up as well.

More details can be found at https://www.efanniemae.com/sf/mortgageproducts/index.jsp