Why would you have a "stage 3" clutch in a wrx putting down stock power??
How many miles are on it? If its the stock turbo on an 02 that's been driven regularly over the past 10+ years, then the turbo is most likely done. If its smoking it could be a blown seal and you're smelling the burning oil.
A used td04 is like 100 or less in the forums. Turbo swap isn't too bad, maybe 5 hours of work if you're slow like me.