If you partner into large large projects with other investors, do you have the controlling interest?  

@David HinojosaIf you're partnering up with 3 friends I'd HIGHLY advise making sure that you control the major decisions.

Following are the similarities and differences between the solo 401k and the self-directed IRA.The Self-Directed IRA and Solo 401k SimilaritiesBoth were created by congress for individuals to save for retirement;Both may be invested in alternative investments such as real estate, precious metals tax liens, promissory notes, private company shares, and stocks and mutual funds, to name a few;Both allow for Roth contributions;Both are subject to prohibited transaction rules;Both are subject to federal taxes at time of distribution;Both allow for checkbook control for placing alternative investments;Both may be invested in annuities;Both are protected from creditors;Both allow for nondeductible contributions;Both are prohibited from investing in assets listed under I.R.C. 408(m); andNeither may be invested in your ow business. 

Every year without exception, but I am in a rent control environment and have no other option if I want to stay current.

It's lots of work and I was told by the provider "you have more control in this matter." 

Using the Control and Roll system - you should never need money to accomplish your financial goals. 

Equity partners will have more control, but charge less than other financing. 

Aside from that they have to work it out themselves.Ultimately you risk getting burned but you will have no control over that till it happens.

That way you remain in control. 

Installing multi-zones on a furnace so each apartment can control their own temperature can be challenging and more expensive than with a boiler and hot water.