* If you have a good working relationship with an independent shop, and can talk with their MB tech, describe the values/interpretation you're looking for and pay them for some diagnostic test time. Of course it's not easy to find a shop that will take an honest interest in your project, and even harder to find a shop that will let you past the service writer to talk with a tech.
* A tool that will do live data, some coding, as well as scanning and other functions will likely cost you at least $3K. And that's a lot to spend for just the occational test on your own car. My PC Retriever (Assenmacher Specialty Tools) was around $2500, but I got a discounted price and I already owned a multiplexer which would've added $1K to the cost. Baum Tools has a nice tool also, but it's expensive too. Be wary of cheap equipment. Comparison shop. You might be able to find a reliable used high quality tool on eBay, or from a member of this site. Good luck.