The "proper tune" being big brands which aren't even tuned by most of the resellers is a comical topic.
Many of the "dealers" for them are flashing generic maps of theirs nonchalantly.

Remember it's not all about claimed figures, anyone can push for numbers at the risk of your motor or turbo just so you can say it makes xxx amount of power.
It's about reliability as well as drivability.
What area are you located in?