A dozen years ago the answer would have been to upgrade the air cleaner and install a free flowing exhaust, followed by a good tune, to get a Stage I improvement. That was when the stock air cleaners were quite restrictive. With late model bikes that come standard with the Ventilator air cleaner, you already have the equivalent of the Stage I air cleaner. If I was you, I'd wait on doing air cleaner updates until you make other changes that will increase the breathing capabilities of the engine. That would be things like head work, larger throttle bodies, larger displacement, higher performance cams.
As for tuning, TTS is probably the most capable system on the market for knowledgeable users/tuners. A more important question involves not the system, but who you plan to have use that system to actually tune your bike. Spend a lot more time on finding the best tuner, and then let that person help you decide what system to use. If you're just planning to use a tuning system to load canned maps, then you need to research which company has the best library of maps for your bike and your planned changes.
JMHO - Jerry