Modern automobiles come with a ballpark tune that's very conservative. This makes it useable in many climates all around the world. Generally speaking there's room for optimization in most situations.
If a tune-able engine management system became available from a reputable company i would definitely buy one. But that's probably never gonna happen for the CX-5.
Naturally aspirated cars, like forced induction vehicles, typically run very rich as rpms increase during wide open throttle as well as very modest timing advance all during open loop commanding. Improvements can be had here. I had a Lancer back in 2001 that i had tune-able engine management for and that was exactly what we did. I ran 93 octane fuel, leaned out the afr's and added timing until we seen EGT's increase then backed off a tad. It made a huge difference. Acceleration was much stronger than before and highway passing power was greatly improved. For a little lancer with just bolt-ons that little guy could move. It even kept up with a friends V-6 eclipse, much to his surprise. I ran that car for a few years like that and never had a problem. In fact, its still running.
I'm aware this is not an accurate comparison as new cars ecu logic is much more complex these days.