A dirty filter causes the HVAC to run harder to suck more air in the return, which translates to more energy. 

The usual surface remodel stuff you'll have no problems with (painting, new fixtures, appliances, flooring, cabinets, etc.) but once you start altering floorplans or moving electric or plumbing, it's generally smarter to get the permit (unless it's for your own house and you don't care about the resale value and are comfortable with the risk).Also remember that while this stuff pertains to the county and state rules, individual HOA's also have their own rules and some require that all work be done permitted and/or by licensed contractors. 

(g)Protection of medical information(1)Limitation on consumer reporting agenciesA consumer reporting agency shall not furnish for employment purposes, or in connection with a credit or insurance transaction, a consumer report that contains medical information (other than medical contact information treated in the manner required under section 1681c(a)(6) of this title) about a consumer, unless—(A)if furnished in connection with an insurance transaction, the consumer affirmatively consents to the furnishing of the report;(B)if furnished for employment purposes or in connection with a credit transaction—(i)the information to be furnished is relevant to process or effect the employment or credit transaction; and(ii)the consumer provides specific written consent for the furnishing of the report that describes in clear and conspicuous language the use for which the information will be furnished; or(C)the information to be furnished pertains solely to transactions, accounts, or balances relating to debts arising from the receipt of medical services, products, or devises, where such information, other than account status or amounts, is restricted or reported using codes that do not identify, or do not provide information sufficient to infer, the specific provider or the nature of such services, products, or devices, as provided in section 1681c(a)(6) of this title.(2)Limitation on creditorsExcept as permitted pursuant to paragraph (3)(C) or regulations prescribed under paragraph (5)(A), a creditor shall not obtain or use medical information (other than medical information treated in the manner required under section 1681c(a)(6) of this title) pertaining to a consumer in connection with any determination of the consumer’s eligibility, or continued eligibility, for credit.(3)Actions authorized by Federal law, insurance activities and regulatory determinationsSection 1681a(d)(3) of this title shall not be construed so as to treat information or any communication of information as a consumer report if the information or communication is disclosed—(A)in connection with the business of insurance or annuities, including the activities described in section 18B of the model Privacy of Consumer Financial and Health Information Regulation issued by the National Association of Insurance Commissioners (as in effect on January 1, 2003);(B)for any purpose permitted without authorization under the Standards for Individually Identifiable Health Information promulgated by the Department of Health and Human Services pursuant to the Health Insurance Portability and Accountability Act of 1996, or referred to under section 1179 of such Act,1 or described in section 6802(e) of this title; or(C)as otherwise determined to be necessary and appropriate, by regulation or order, by the Bureau or the applicable State insurance authority (with respect to any person engaged in providing insurance or annuities).(4)Limitation on redisclosure of medical informationAny person that receives medical information pursuant to paragraph (1) or (3) shall not disclose such information to any other person, except as necessary to carry out the purpose for which the information was initially disclosed, or as otherwise permitted by statute, regulation, or order.(5)Regulations and effective date for paragraph (2)(A) [2] Regulations requiredThe Bureau may, after notice and opportunity for comment, prescribe regulations that permit transactions under paragraph (2) that are determined to be necessary and appropriate to protect legitimate operational, transactional, risk, consumer, and other needs (and which shall include permitting actions necessary for administrative verification purposes), consistent with the intent of paragraph (2) to restrict the use of medical information for inappropriate purposes.(6)Coordination with other lawsNo provision of this subsection shall be construed as altering, affecting, or superseding the applicability of any other provision of Federal law relating to medical confidentiality.

The cash flow that comes in from my OOS investments may outperform my in-state investments on paper, but that doesn't necessarily translate to actual or overall ROI.To all of those saying you cannot make money in expensive markets (SF, LA, NYC, etc) I don't understand that mindset.

Instead, they mask it as a violation under "alteration" paragraphs.

The answer, as it always is, is hidden in the problem...in plain sight.Here's what you're asking, translated to math:Property Cost:  $100kOption A:  20% Down (4%/30yrs)DP = $20kMonthly Pmts - $382/mOption B: 25% Down (3.25%/30yrs)DP = $25kMonthly Pmts - $326/mDifference in DP in Cash (what matters) = $5kDifference in CF (what also matters) = $56/mNumber of months to recover the difference (Added cost) in DP:  89 months/7.5 yearsIn other words, you are pre-paying $5k in cash upfront, to get $56/month in extra CF. 

May need to taken it down to the stud, remediate electrical hazard, get all the additions and alterations brought back to code or demolished, possible asbestos abatement, lead paint remediation, water fixture upgrade to the new code.Estimates from a couple of contractors run anywhere from 150-200K to rehab this property.

For example a 3 bedroom home could be a four bedroom if the layout was altered.

However, realize the direct and indirect costs associated with having one.As mentioned, you will need to keep the entity as separate to protect its corporate veil so don't co-mingle your funds and use it as an alter-ego for example.Also, legal entities such as LLC's are not eligible for conforming residential loans. 

There are many posts, many I've written, about how that screws you up with both co-mingling and alter-ego thus piercing your corporate veil.