Powertrains with more speeds have thinner gears that wear out faster and cost more and they don't really offer any advantage.

Upgrade your tyres to Marathon Supremes and the brake pads for Kool stop pinks, add Ergon grips - you'll go faster, have fewer punctures, and be able to stop in the wet. And put security skewers on the wheels and seat post if you ever leave the bike locked on the street.