The upgrades will make it easier for the tenant to rationalize the increase in rent. 

In the long run, I recommend increasing your standards a little to help weed some of these people out.When I process an application, I use a score sheet with different criteria like length of employment, rent-to-income ration, credit score, landlord references, etc.

But generally, MF owners are more rational financial actors, so it would be harder to find one on the general market.So I'm having a hard time figuring out how I'd go about finding undervalued off-market MF properties.David mentioned MF meetup groups, but wouldn't the people you meet there also be looking to make profitable sales?  

I calculated my current debt to income ration at 37%.

LOL.cars are a hard one to rationalize... and everyone has an opinion .

I got mine down to 2%.A rational number would be one month vacancy per unit per year, or 8%

There is a part of me that is interested in flipping, however the rational side of me says I should probably stick with one thing or the other.  

That's not investing...that's speculating, guessing, hoping, rationalizing(most expensive word a REI can use)...pick your word.

If you are ok with the rent discount and need to rationalize it somehow.  

People who don't make rational decisions, which is the whole reason why I'd be evicting at all, get really messed up about their finances at this time of year and under the stress of the eviction they know is coming.