Auto Express speculates that the 4 will ride on a platform called SEA, which is related to the PMA architecture developed by China-based parent company Geely. If that's accurate, the 4 will become the first Polestar model not built on Volvo bones. The 1 is on the same Scalable Production Architecture (SPA) platform as numerous Volvo models, including the current-generation XC90. The 3 will reportedly ride on the next evolution of this architecture, while the 2 is built on the same basic Compact Modular Architecture (CMA) as the XC40 and the C40.