This paper investigates an analysis of variable gate-drive strength (GDS) in Silicon Carbide (SiC) inverters with interior permanent magnet synchronous machines (IPMSMs) for electric vehicle (EV) traction drives. While SiC inverters offer superior efficiency and performance at high switching frequencies, their fast switching transients result in high dVds/dt and dids/dt, leading to overshoot, electromagnetic interference (EMI), and increased harmonic losses in the motor. This study evaluates the impact of strong and weak GDS configurations on both inverter switching losses and motor efficiency using a co-simulation process that integrates circuit simulation, control modeling, and finite element analysis (FEA). Experimental validation on a 300 kW SiC inverter and IPMSM using a dynamometer further demonstrates the trade-offs between inverter and motor performance under varying operating conditions. By addressing the system-level effects of GDS selection, an insight into achieving a balanced and efficient design for SiC-based EV powertrains is presented.