Good Questions
You should check out - tradingwithmatlab.com
It is possible to implement an automated trading system for free using matlab and interactive broker's trader work station API.
One problem you may run into is getting the data you want if you need a specific type of data to...
Using exchangeapi you are forced to only use their functions.
If you write the code yourself than you can have whatever functionality that TWS API will allow for.
I strongly suggest you write the code yourself, it's free and keeps a lot of doors open.
for help visit tradingwithmatlab.com
I'm trying to create a central repository for files/info for those trying to trade with matlab.
It seems like most of the other sites have stale data......
check it out:
www.tradingwithmatlab.com/