Cobra F1 slip-ons sound *ok*....but they're a little ugly IMO. Stock-looking polished canister, with a big red F1 slapped on the side. No cool logo, no metal badge...just a big, tacky F1.
I've heard sound clips of Sarachu pipes and I have to say I'm very impressed. They sound AWESOME...but they ARE pretty loud. Filip has the Sarachus, maybe he'll chime in on the volume and sound characteristics of them.
Edit: Nevermind! Looks like you got your Sarachus!