With your fix and flip and construction experience I'm sure you've familiar with dealing with them and may already have gotten the process started.Next as @Matt M. mentioned, a mechanic shop is going to need cleanup (environmental abatement) that could add to your cost.A consultant is definitely wise.  

My business has never been better and grows year over year.I think some buyers get intrigued by NNN and it's passive component.

They look into title issues, environmental hazards, flood likelhood, zoning, encroachments, pest infestations, CCR's, comps, plumbing, electrical, safety, structural, radon, sex offenders, planned highway projects, etc.   

I want to know the current condition and life expectancy of all major components and appliances. 

I'd disagree on the property management component point. 

I was wondering since auction.com does have that list, liens exceptions list:"Most liens are removed after a foreclosure property sale, but certain liens may remain.Here are some examples:Any lien recorded on title prior in time to the foreclosing mortgage.First Mortgage (if the foreclosing mortgage is a second or third mortgage)HOA or COA assessment liens (in certain states)Mechanic’s Liens (in some states)Government liens such as state and federal tax liens, city or county liens, US Government liens.IRS liens (IRS may buy the property within 120 days after sale at the price paid at foreclosure sale)Code Enforcement Liens, Environmental Liens, and Utility LiensChild Support Liens"How did you go about making sure these liens exceptions as specified on auction.com are covered in your ultimate title insurance policy?

I must be missing something - is it the additional maintenance/expense component of managing rentals?

I've been looking at cash flows from the following two perspectives: 1 - Cash in, less cash out, less allowances (this includes P&I, taxes, all expenses, plus all allowances ~10% vacancy, 10% prop management, 5% repairs). 2 - 50% rule - so NOI, compared to P&I. i think in both of the scenarios above, the P&I component ends up being an indicator of cash flow (assuming that we aren't purchasing a property where the rents are nonexistant).

We manage many houses in tough neighborhoods (see below for a list of the 6 zips where we manage over 100 units) and we follow the same model Alex described above about securing the property (eg, boarding windows, removing components, etc.).  

. $7 ($7,000 total); Useful life 20 years (240 months) = monthly roof CapEx accrual ($7000/240) = (a) $29.17 Water Heater - replacement cost of $1,000; Useful life 10 years (120 months) = monthly water heater CapEx accrual ($1000/120) = (b) $8.33Kitchen Appliances - replacement cost of $1,000; Useful life 10 years (120 months) = monthly kitchen appliances CapEx accrual ($1000/120) = (c) $8.33Driveway/Parking Lot - replacement cost $5,000; Useful life 50 years (600 months) = monthly driveway/parking lot CapEx ($5,000/600) = (d) $8.33HVAC - replacement cost $3,000; Useful life 10 years (120 months) = monthly HVAC CapEx ($3000/120) = (e) $25Flooring - replacement cost $2,000; Useful life 5 years (60 months) = monthly flooring CapEx ($2,000/60) = (f) $33.33Plumbing - replacement cost $3,000; useful life 30 years (360 months) = monthly plumbing CapEx ($3,000/360) = (g) $8.33Windows - replacement cost $5,000; useful life 30 years (360 months) = monthly windows CapEx ($5,000/360) = (h) $13.89Paint - replacement cost $2,500; useful life 5 years (60 months) = monthly paint CapEx ($2,500/60) = (i) $41.67Cabinets/Counters - replacement cost $3,000; useful life 20 years (240 months) = monthly cabinets/counters CapEx ($3,000/240) = (j) $12.50Structure (foundation/framing) - replacement cost $10,000; useful life 50 years (600 months) = monthly structure CapEx ($10,000/600) = (k) $16.67Components (garage door, etc) - replacement cost $1,000; useful life 10 years (120 months) = monthly component CapEx ($1,000/120) = (l) $8.33Landscaping - replacement cost $1,000useful life 10 years (120 months) = monthly landscaping CapEx ($1,000/120) = (m) $8.33Sum of (a) through (m) = apx $214/mo for my CapEx accrual - Does my approach make sense and does it seem reasonable?