I've read that SAR proliferation is becoming a real problem though, in that there are just gillions of them reported. Mainly because financial insitutions will "defensively" file one for just about any reason as a CYA move.
Unfortunately, I don't remember any stats about the ratio compared to CTRs. They're not automatic like CTRs, but they can be done for any dollar amount. Hell, I realized in hindsight that when I went up to the cashier with $500 in twenties, and wanted them changed for hundreds, that could have looked kind of suspicious.
Regardless, if you start getting tagged with CTRs or SARs, it goes to somebody at the Treasury department. But it is not a tax document, so it doesn't go automatically to the IRS. That doesn't meant it won't go to the IRS, especially if you were audited.