You could end up loosing the deal to the next investor. 

And likely will end up as essentially the same as selling loose cigarettes.  

In some locations if your tenants complain about something then you are automatically on the defense (more than ordinarily) and for some issues, like enforcing a lease, you loose because you didn't have the legal authority to lease that part of the building as a dwelling unit.

The downside is the variable rate - not an issue during the past 5 years or so, but sooner or later they are bound to go up.

I would not have a yard sale because vacant property tend to loose copper plumbing quickly and that would offset any extra value.

I am bound by ethics and morals.

It takes a certain personality to deal with homeowners who are loosing their house.

Or...maybe I can "loose" the money on the improvement and enjoy it and let the improvement help move the house quicker rather than drop the price the equivalent amount.

You may be fighting a loosing battle.

Took awhile for me to finally decide to do it but now that I'm over my initial fear I don't want to loose my momentum.