With that said, I know that @Brandon Turner has said (if I remember correctly) on the podcast that he likes to get at least 12% cash on cash return and something like $200+/month in cashflow.In the stock market I am confident in about an 8% return over the long run so I obviously want to get a better return than that if I am going through the work of buying a property and also managing the rental.

Vacancies mostly depend on how improved is the property - condition.

I only have about 15k in savings and didn't see much improvement over the 10 years and would like to start investing into real estate since its a great way to earn cash on cash return. 

This provides another level of confidence in the property management service you are getting.In the past there were instances for which they waived some of the PM fees that were listed in the PM agreement.

It is good to run the numbers, but the most important thing is to know the location you are looking at and what sales prices and rents the neighborhood can support.The price for this place is $272k and that is the short sale price, i have spoken to the agent and that is the best they can do.Rents are likely between $1200-$1300 per floor, no real need to improve the units as the neighborhood is unlikely to support higher rents at this time. 

Monthly cashflow improved by $150 from the debt restructure.  

If you are talking about capex like a new roof, new flooring, or other major improvements then I would use the HELOC.You want to use the cash for more investments that will bring a return.

To really have confidence to move forward you need to know the market.

I only put the down payment and about 20k of capital improvements into it and have brought the income up 60% per month.

For the box size of the car wash you would need to see what rent per sq ft they are paying for the market and make sure it was not inflated with TI (tenant improvements) from the developer.