There's two ways to upgrade the range without reengineering the vehicle for a larger pack: 1) improved chemistries (increasing kWh), and 2) improved efficiencies (which also improves effective charge rates). The latter should be easier than it first sounds: replacing the front motor with the PMSRM used in the Model 3 (at least in the non-P100D variants). It's already in mass production, after all, and looks to be sufficiently compact. Bet it offers nearly a 10% increase in efficiency.
The very exciting part is V3 supercharging, since Model 3 and all new S and X are supposed to be rated to higher powers than existing Superchargers can supply. According to Ingineerix, the charge cable in the Model 3 is rated by its manufacturer to 430A, although EPA docs say 525A. That'd be ~150kW and ~180kW at low SoCs, respectively. In a "proper case" (some people are inexplicably not encountering "proper cases"... whether it's the vehicle or charger to blame, it's not clear), taper doesn't begin until nearly 50% at ~120kW, so taking those sorts of powers at low SoCs seems quite plausible.