I will lose my DPA but I think I can come up with 6k between my Roth IRA and some money owed to me. 

Gregg,you can set up a self-directed IRA or 401k, which in turn can be used to make alternative investments.

Living below my means and resisting temptations for years, let alone contributing to IRA account, I have accumulated some savings.

I also understood that that one of the disadvantages of using an IRA to invest in real estate is that you can't use depreciation to offset your income tax. 

its a nice niche , most of our folks use their solo K's and Ira's for the performers.

As an FYI, I'm aware of self-directed IRAs; however, that strategy does not align with my current real estate goals.

I am looking for some advice and comparisons between a Self-Directed IRA vs a Solo 401K.  

This is true whether you have a Solo 401k or IRA LLC with checkbook control or a retirement structure held with a self-directed custodian.

@Caleb ChildsWith a self-directed IRA or Solo 401(k), there can be no direct or indirect transactions or benefit between the plan and you or other family members viewed as disqualified to the IRA. 

Also An IRA custodian I know would question the acquisition.