300L mods and break in

Just bought a ‘24 crf300L and plan on doing the 550 performance 91 octane stage 1.0 mods. I have everything else, but the ECU is still in transit. Should I wait til first oil change to install everything? I’m itching to install the new exhaust because I hate the Vespa scooter sound of the stock pipe! Assuming I still keep it in the low to mid rev range, would it be a bad idea to start the performance mods while still in the break in period?