I haven't had my 2013 E93 M3 long, but thanks to this forum was already looking at all the cool changes and mods you can do to it.
Last week I had some coding changes performed remotely by Mike B at BPMSport. Then this week I finalized the coding and had the ECU tuned. All I can say is WOW!
I took it out just to get a feel for any changes and it's like a whole new car again! Kudos to Mike for creating such an easy process for people to follow to get these features added to their car. I thought about learning to code it myself, but I work on the other side of the US and just don't have time to learn it - let alone make ANY mistakes.
Mike's changes were awesome. Even without M activated (EDC off, Power On, DSC on) it still has this 'uncaged' feeling to it. Activating the M (EDC Sport, Power Plus, DSC Euro MDM) it is an animal!
When we bought our 911 C4S we drove a turbo to see how we liked it and I remember telling the guy, 400hp with turbos should give me that HAND OF GOD feeling when they spool up. I just wasn't getting that feeling in the 911 turbo. I was a bit disappointed - hence the C4S sitting in our garage. But the M3 gives me everything that I was looking for in the Porsche and more. I am so in love with this car.
If you're looking for an easy upgrade, check Mike out. Funny, easy going, and all around nice guy.
/obligatory - I am in no way affiliated with BPMSport.