Exhaust with cat remove enough or also change to the motor electronics necessary ?

Hello. The BMW M 535 i has only 185 hp with Kat but without Kat 218 hp (!). That’s a huge difference. – If I buy one now with Kat, then it is enough to exchange the exhaust with Kat for one without Kat or there must also be changes to the motor electronics, so that nothing “mistakes” ? Thank you. Greetings, Thorsten