Yup. Not a new thing. The first thing to ask is how much boost you get at WOT? Should be at least 9-10 psi this time of year. The colder air is denser.
If your boost is good, we're looking at a coupler (hopefully) or a gear/bearing failure on it'* way. You can get just the nosedrive assembly if the impellers are good and you have good boost.
It'* not really that big of a deal to do this. Couplers are cheap, but you really need to open the nosedrive (remove it from the SC) to determine this.
Isolating the noise to your OWN satisfaction is the first step. Use a stethescope or screwdriver held to your ear in the same manner (careful of moving parts, screwdrivers are a bitch to remove from your ear), and be sure that'* where the noise is coming from, then determine what KIND of noise it is. We can take it from there. Let us know how much boost you get under WOT, and what you find out about this pesky little noise.