I just got the APR stage 1 tune and have been running the 93 octane program for about three days. I haven't beat on it at all, and just today my turbo has been starting to whine(Yes, I know the turbo is supposed to have a whine, but it started sounding more like a supercharger).

I read online that some people ignore this sound and it ends up nearly destroying their engine, some people never have problems, some people say it is a bad bearing or turbo, and some say it a bad up pipe in the cat.

I threw a 2181 engine code a couple weeks ago before I drove 20 hours for vacation, which refers to the cat.

Any personal experiences with this?
Also, if I need a new turbo, does anyone have a stock turbo I can buy from them?