Upgrade motor replacement for Sta-Rite Max-E-Glas

Living in CA I’M not allowed to replace my single speed pool pump with a single speed replacement motor (title 20). Currently my existing pool pump is a Max-E-Glas 2hp Model  K48M2PA104. I believe it was purchased in 1987. So I’m replacing just the motor and necessary parts with a 3hp Sta-Rite Intelliflow EVSS3. My pool is a 55,000 gunite pool. The 2hp pool pump appeared to work only adequately. I’m using a 600 lb sand filter. Should I replace the Impeller and diffuser to the 3hp parts listed in your parts list in order to benefit to a higher hp motor. Also, will this upgrade attach to the motor attachment plate or do I need to replace the attachment plate? Any other informational help will be appreciate. After I reeceive your response I will be ordering the necessary parts. Thank you for your assistance. John…