The Atkinson-cycle engine built to sip, not scoot

Honestly, there's very little worth tuning here. It's a naturally aspirated Atkinson-cycle engine with no boost to play with, so any ECU remap nets only a handful of kW - not enough to justify the spend. If you want a faster Kona, the move is the turbo 1.6 T-GDi or the Kona N, which respond properly to tuning.

Focus on the basics rather than power: a quality cabin/engine air filter, fresh fluids, and decent tyres will do more for how it drives day to day. A panel filter or aftermarket intake might free up a faint bit of induction noise but won't add meaningful performance.

Not in any way you'll feel. On a non-turbo Atkinson engine, a cat-back or intake is mostly about sound, and even then the gains are tiny. We'd only fit one if you specifically want the note, not because you're chasing kilowatts.

The Nu engine and 6-speed auto are well-proven and generally trouble-free - this is one of Hyundai's more dependable drivetrains. Keep on top of servicing and transmission fluid, and it'll just keep going. There's no fragile turbo or DCT to worry about on this variant.