Sure, every requirement adds a few percent to the building cost.

The combo of the 24x7 dehumidifier and black plastic made a zillion percent improvement in the basement. 

Then agent gets 60-100%.depending on arrangement with their broker.If a broker brings you a buyer that is 4 percent more than you wanted, give the broker 3% and your still ahead.I always, always have an agent sell my houses/properties.It will be on the open market and generally the open market will bring your property to top  price.Hopefully a bidding war will start and you will end up with so much more than 6 %.Is your property desirable?

How valuable would a tool that can automatically compare and rank all the properties you are interested in based on expected percent upside be?

About three-fifty.  

And you might even win if it's a percent or two lower than a financed offer. 

Have been renting it out since 2008. 2nd update in 2018 (new paint, new flooring after renters damaged old pergo floors - went with 100% vinyl flooring with lifetime warranty.)

Have been renting it out since 2008. 2nd update in 2018 (new paint, new flooring after renters damaged old pergo floors - went with 100% vinyl flooring with lifetime warranty.)

Since the interest rates dropped a whole percent since we closed on our home we looked into refinancing our home.

You are 100 percent right, the best thing to do is actually get out there and do one.