@Leland SmithPennsylvania has a high transfer tax.  At

Profits from flipping at the volume you appear to be operating at would more likely be considered self-employment income subject to regular taxation plus self-employment taxes.In that case, being able to shelter some of that income from taxation by contributing to a Solo 401(k) could be advantageous.  

That's way before you get into the taxation issues. 

Unless you are forming an LLC or are getting the  money from a complicated taxation withdrawal, I don't see the need.

Under the new tax law, is there a benefit to changing the tax status of my LLC? I was listening to a podcast when the speaker mentioned that some RE investors were changing the tax status of their LLC to be taxed as a...

If you know how to predict those - teach me.But if you do flipping, the resulting income will be counted for the taxation of SS benefits, no matter how you structure it.

@Josh Caldwell it might be worth having your attorney and CPA look into clauses that address taxation, foreign asset control regulations and economic impacts.

@Steve Rogers did you pay any tax at that time?

. , Based on what I have seen here, International taxation is not discussed here as much and it is complicated. 

I charge just enough to pay certain bills that cannot go on my schedule E, such as medical insurance, but so much so I would have double taxation problems.