The answer, as it always is, is hidden in the problem...in plain sight.Here's what you're asking, translated to math:Property Cost:  $100kOption A:  20% Down (4%/30yrs)DP = $20kMonthly Pmts - $382/mOption B: 25% Down (3.25%/30yrs)DP = $25kMonthly Pmts - $326/mDifference in DP in Cash (what matters) = $5kDifference in CF (what also matters) = $56/mNumber of months to recover the difference (Added cost) in DP:  89 months/7.5 yearsIn other words, you are pre-paying $5k in cash upfront, to get $56/month in extra CF. 

May need to taken it down to the stud, remediate electrical hazard, get all the additions and alterations brought back to code or demolished, possible asbestos abatement, lead paint remediation, water fixture upgrade to the new code.Estimates from a couple of contractors run anywhere from 150-200K to rehab this property.

For example a 3 bedroom home could be a four bedroom if the layout was altered.

However, realize the direct and indirect costs associated with having one.As mentioned, you will need to keep the entity as separate to protect its corporate veil so don't co-mingle your funds and use it as an alter-ego for example.Also, legal entities such as LLC's are not eligible for conforming residential loans. 

There are many posts, many I've written, about how that screws you up with both co-mingling and alter-ego thus piercing your corporate veil. 

Permitting for residential renovations may apply in cases where you’re making additions or alterations.

They also can alter when you can rent or how often. 

That translated to $144,000 per year… so more than triple what the 4% rule would allow.  

And if you end up 1031ing after a year or two in a hot sellers market it's conceivable that you have 25% equity left after the refi plus an additional 10-15% from appreciation. which translates to almost 40% equity. 

My sister helped translate.