Okay, my sister wanted me to ask you guys some weird questions.

She wants to improve the looks of her Altis' tailpipe into one of those round, silver thingies that you'd often see on Hondas. Not only that, she also wants her Altis to sound deep whenever revving high, but, she doesn't want that loud "racing" sound that the aforementioned Hondas create.

Is there such a "thing" that would give her a deep and yet silenced, non-racing sound?

Would such change/s be detrimental to her car's performance?