Sparr shrugged. "Done it clean. Could have cut corners. Didn't."

Evan sat across the table and read Sparr's notes, nodding slowly. "You ever thought about teaching that? Not the hacks, I mean the honest stuff. People need to know there's a line."

The manager's gaze flicked from the tablet to Sparr. "Costs money."

The shop's radio chattered with a morning DJ's joke about traffic. Sparr toggled between windows, double-checking torque curves and safety margins. Every change he saved wrote a promise into silicon; every rollback was a mercy. He finished the tuning and ran a road test, riding shotgun in the courier's greying Transit van as it climbed the neighborhood’s steep spine. The van felt softer, more willing—no sudden lurches, no lag at merges. Sparrow, the city falcon nesting on a nearby rooftop, bobbed as if taking measure.

Sparr kept his hands steady even as the fluorescent shop light hummed and the rain ticked the corrugated roof. Around him the garage smelled of oil, hot plastic, and a dozen half-finished promises. His toolbox lay open like a confession; wires curled out of it as if reluctant to reveal the truths they carried.

He plugged in the diagnostic dongle and watched the laptop’s black screen bloom with green text. Lines of code streamed by like a language of their own. Modern ECUs were cages of logic and thresholds that decided how much fuel sprayed, when ignition sparked, and how aggressively the turbo spat. There was artistry in rewriting them; a line here, a curve there, and the whole personality of a vehicle shifted subtly—sometimes beautifully, sometimes dangerously.