So let's say the purchase price is indeed $252k.20% down, 30 year fixed rate loan at 7.5%Monthly payment would be $1,410Property Taxes would be at least $2000/yr given that it is not homesteaded - so at least 165/monthInsurance will be around 80 to 100/month - we'll say 80/monthSo we are now at 1655/month before vacancy and capital expenses.You quote renting to a Section 8 tenant - I'd add $2400 in cap ex per year then. 

You will find most lenders cap at 90% towards the purchase price and 100% of the rehab. 

$$ per door, CAP rate, or something else?

I'm basing what I see off the 1% rule for SFH, and cap rate values based on 50% rule for multi-family.Again thanks in advance.

Seller reports NOI: 108,101, Gross carwash income: 149,546, Cap Rate: 11.5%.

A rural-marked appraisal will be capped at 65% LTV; vacant is OK on purchases and refinances with less than 6-month seasoning.

They have no understanding of compound interest, time value of money, return on investment, cap rate, or anything involving math of any sort10.

You paid $2m for it two years ago w/ 25% down (it was suffering from mismanagement and deferred maintenance), invested $325k in capital improvements, and it's now valued at $3m with an NOI of $195k (cap rate assuming $3m value is 6.5%).

I've calculated the cap rates and they are all generally similar (~4.5%).

Indio is currently STR friendly as well as the HOA but I've heard there may be caps coming soon by the HOA - we wouldn't have to worry yet.