Depending on the amount of commission income you receive, this may be the first step to take that causes the highest impact on your tax return.  2) How a SEP IRA plan may help you out.  

I’m just about to join a syndicated real estate investment.I will personally guarantee a large loan.My question is:Are my retirement accounts (IRAs, 401K, 403B, TSP) protected?

We are new to owner financing but own a property under a self directed IRA and are considering all options.  

A financial advisor can help you work out the specifics of your situation but investing in your company's 401k and perhaps a Roth IRA are a good place to start. 

My investment was in SD IRA and now in big trouble to pay loan because management company stealing all money from current rental income.

@Anthony HerbertPretty much any self-directed IRA provider is going to be "safe".  

This makes a lot of sense to me and I've been doing this for years through the traditional routes of 401(K) and Roth IRA.  

I met with a self-directed IRA custodian yesterday.  

I also am seeking someone who has indept knowledge/ experience in figuring out the best way to buying an investment property i.e HELOC, HML, self-directed 401k/ira conventional loan?!

Of course, maxing out your 401k and IRA contributions is often a good start.