Just be sure that the deal is solid, you perform your D.D. and you're working with people that know the market and will give you "correct" and "accurate" information.  

I have had a very profitable business purchasing non-performing, seller financed real estate secured notes.  

On the subject of non performing notes, When discussing and implementing a loan modification with the borrower, are there usually state laws or regulations (In general and/or at all) that come into play and how much do they affect loan modifications or if at all?

As mentioned we haven't performed any new construction on our own in Los Angeles.

However, there are several case studies of "cost effectively" built houses which achieve "near Passivhaus" performance (i.e. 20 - 35 kWh/m^2) per year.  

Either you or a representative you trust with out exception must perform all the necessary due diligence just as you would for a property down the street from you.Turnkey companies want to maximize profit by doing as little work as possible using the cheapest materials.I would have a professional inspector check everything with a fine tooth comb,especially the roof,plumbing,electrical,and HVAC systems.Also make sure you get a repair warranty for when things go to hell in two years or less(and they will).I honestly don't trust any property I don't rebuild myself with my trusted contractor and quality materials that will last at least a decade or more

Here is a part of the letter, I sent to the seller:The home inspection was completed on September 29th (please see attached) and the following issues were pointed out: 1.The wooden floor frame in the middle unit is deteriorating due to either prior water leak in the bathroom or due to moisture infiltration through the walls and foundation.2.There is evidence of significant settlement under the middle unit bathroom and north closet.3.The settlement of the floor and walls has also resulted in settlement of the roof frame above this area, ceiling shows cracks.4.There is an obvious depression on the roof – water is ponding on the roof above the middle unit, which adds excessive weight on the roof and potential for leaks.5.Asbestos containing material has been found.6.The current bedroom heat installations in the north and south units pose a safety hazard from carbon monoxide, fire and oxygen depletion.7.An electrician performing upgrades did not use ‘arc fault breakers’ in the north and south unit breaker panels, which is required by the national electrical code.8.Upgrades to the electrical system, promised by a real estate agent, have not been completed yet.

My basic was using the 75% factor for a long while but now due to my longevity of performance and relationship with them, they now loan me 80% Of the appraised value, interest only for 1 year. 

Of course past performance is not necessarily an indicator of future performance.

I am looking to invest in real estate notes (preferably performing notes under 30k) Any recommendations  on reliable note investing companies with a high success rate?