I’ve owned an IS-F (and RCF). They are muted. You can stick an aftermarket exhaust on them, but I disliked the associated drone. A C63 of that era wins hands down noise wise. The best part of the Lexus sound track is the induction noise - but you have to be gunning it to make the most of it.
Outside of the noise, the ISF wins on every count in my opinion.
I’m not biased by the way, I drive a 63 (w205)
God luck!