Not quite the Doomsday scenario Elon Musk is afraid of, but certainly a reasonable concern.Additionally, with Berkshire’s surging cash pile nearing $200 billion, it is difficult for Berkshire to find a way to deploy capital effectively in a way that “moves the needle”.

Then I started thinking, perhaps I could acquire a turnkey 2b1b and do an addition to force appreciation and refi on the backend with a larger 3b2b and still effectively BRRRR and have a new rental in my portfolio.

Margins aren't high enough.

If you are working your local market, there are other methods of finding leads that are more effective than cards or letters . . . see what is working in your area from REIG members.

But the comps were pretty high for this house.

For example, if the market rent on the duplex unit you'd like to occupy is $500/mo, you can go rent another similar unit for $500 (-$500/mo on your personal bank account) and rent out the units owned by your Solo 401k (+$500/mo for your Solo 401k).As you can see, -$500 and +$500 equal the same net effect in the short term, but long term, you'll accumulate wealth more rapidly because when you go to reinvest the cashflow from the 401k-owned unit you were going to occupy (but rented out instead), the tax benefits of full reinvestment will add up faster.How do I pay the returns back to the 401(k)?

Purpose is for a high end coliving project.

I enjoyed the process, but rates are very high right now. 

But $40k is way, way too high a price.

This effectively means that I don't need a primary residence at least for the next few years and my living expenses are practically 0.