I suppose in the long run it will be an asset since you can target the most promising markets instead of sticking to what you are comfortable with.

I'm starting to target pre foreclosures.

My target market is very dense, and very hot.

I know I can dig through sold listings individually, but didn't know if anyone has found a way to aggregate the necessary data to see lists of homes which were sold twice within a designated period of time, chart the spreads, possibly see pics of the results, etc.I'm spending a lot of time scrolling through sold listings in my target area/price range to try and develop a gut feel for what homes are selling for and in what condition.

I have been able to expand from 5 units to 15 units over the last 18 months by getting to know my target market, getting tapped into resources & developing a team in that area and staying on top of things. 

You definitely don't want to be penny wise and pound foolish when it comes to properly covering your assets. 

For example, mixing in flips, focus on the BRRRR method, targeting larger buildings, etc.Similarly, what would you deem the next step forward for someone who has focused solely on buy and hold single families? 

You are not involve in the commission part, however, you need to understand and be careful about the properties price in your target area.

2- Every investor needs to sign a contract after he purchase a home that he is going to rehab the house in a mount of time, so no house in a target street will left with no rehab.Regards,,,

What type of leads are you going to target?