Noticeably, but not too much.
This youtube video might help with how to locate & change it.
Don't mind the language, and that it's RHD, (so on passenger side on ours).
Get pliers for ring removal & marker, to ease inserting it with angle to right side. Will ease putting it back.
Pros of soundtube - better then nothing at all, makes it louder on inside but not on outside (for neighbours / cops). It's cheap mod, especially if you mod original. One can also quickly change it, from a bit louder, to stock, to completely close it (using eg. cig lighter plug from glovebox to close soundtube hole inside car)
Cons - artificialness of sound, some don't like, passing more road noise in, wooshing intake sounds. And soundtube deletion can cleanup a lot underbonnet space/add though slight but weight savings. Proper catback exhaust upgrade will do better audible pleasure wise, but will also rise overall loudness outside too .. and will cost much much more.
I don't plan getting catback yet, so am driving with this. Did also experimenting with completely plugging soundtube. It's placebo feeling (soundtube doesn't impact performance in any way. IIRC it's airtight separated in it's construction from intake airflow), but car felt subjectively somewhat dull without this or at least stock soundtube insert, with plugged hole.