The 3” is definitely louder by quite some margin, I thought the tone between them both were about the same. None will get annoying on long rode trips, at cruising speed they aren’t much louder then stock from what I heard. Around town the 3” will be mildly loud while the 2.5 will be pretty tame until you get on it. Personally, I’d choose the 2.5”, I like quieter exhausts on these cars.