The pros are that it would no longer show up on your personal credit and debt to income calculations for other credit purposes.

I have good credit and low debt other than my primary mortgage.

I have 0 debt (besides the mortgages on my two rentals) and my credit score is around 790-800.

They consolidated their loans on all 400 units into a single loan.

You are replacing equity with debt on your balance sheet, not earning additional income. 

In addition, if you are self-employed with no full-time employees you may wish to consider opening a Solo 401k instead of a self-directed IRA as it has several advantages over an IRA LLC such as much higher contribution limits, direct checkbook control (i.e. no need to have the account at a specialty trust company), ability to take a 401k loan, exclusion from unrelated debt finance income tax with respect to investment in real estate acquired with non-recourse financing, etc.In addition, please note if you purchase debt-financed real estate with your IRA, unrelated debt finance income tax should apply to the income attributable to debt-financed real estate held by your IRA.

We have $8000 saved in cash right now and the only debt we have is her car payment which is low interest (5%) and is sitting at $14k right now (we pay $400/month on it which is $100 over the minimum payment but it still allows us to save a lot into our savings accounts).

1) They’re real assets, not paper, and they can’t be easily replaced.2) They produce positive cash flow.3) Apartments appreciate when rents rise, the Multiplier.4) Leverage of debt to increase your position.

A lot of MHP owners who have a large debt servicing could feel the squeeze quick. 

I know that on performing 1st position residential debt an 8-12% yield should be pretty easy to come by.