Please help!!!

[Zwilks14]

Today I was driving to work, and my car was acting as it should. I was on the highway for about 10 miles, and when I went to pass someone to get to the off ramp I noticed my car had a drastic power loss. I got to work and hoped it was a glitch of some sort, and hoped it would be fine on the ride home. It wasn't. Now my car feels like it has the power of a 94 civic. It still accelerates and gets to to highway speeds, but it doesn't do it like it should. There is no kick to it. I started noticing a "whine" type noise last week, I don't know if that is related. Also yesterday I put some stp oil treatment in the engine, but the car ran fine afterwards all last night, and also ran fine 95% of my was to work. Also the exhaust seems louder, please help!?!?!?
Car has maddad whisperer catback, invidia divorced dp, invidia up pipe, spt intake, and Cobb ap. car is a 2005 wrx wagon