Scott The Book on Flipping Houses,The Book on Estimating ReHab Costshttp://www.biggerpockets.com/flippingbookLocate and attend 3 different local REIA club meetings great place to meet people gather resources and info.You might consider Niche or Specialized Housing like student housing.

Right now the estimated value is $150k, an 27% value increase in 2 years!

The 10% of total cost is significantly less than what 50% of the estimated profit would be. 

Do you have an estimate of the cost for installing the AC? 

I just got an estimate of $180,000 to convert existing space into a 3 bedroom apartment.

@John Fields if seller will agree to escrow agreement of 2x the estimated repair costs in escrow and state clearly how you access those funds, that may work if your lender allows.

I like the top performers in the zip feature and being able to show what the top 10-20% make estimated, the middle 50%, and the bottom %.

They offer free estimates. 

I usually use have the yearly appreciation as an estimate of growth. 

If not, then they'd need to come up with a plan we'd be happy with like:  Have us get 2 estimates and get a credit at close equal to the lowest one or something.