2008 Mitsubishi Lancer Engine is REALLY Loud After Oil Chan

I bought a new Lancer March 2008, and had to get used to how loud the engine is. I even took it back into the dealership to have them check it out, and they told me that it's characteristic of the manufacturer. I confirmed this through numerous reviews of the vehicle, so my mind was at ease. Last weekend I got an oil change at a Valvoline instant oil change facility, and noticed instantly as I was leaving that the engine was a lot whinier than normal. When I went to work Monday, I noticed that it gets really loud and buzzy when I try to accelerate quickly, and there is even slight vibration due to the buzz. Any kind of acceleration is loud, but especially when I'm trying to do it quickly. It may be my imagination, but it seems like there is a slight delay and then a lurch when coming out of a complete stop sometimes, and at high speeds on the highway, it's harder to accelerate quickly. I'm thinking a lot of this might be because I try to avoid causing the noise, so my usual driving habits might be affected, and I might not be applying as much pressure to the pedal as I normally would. Due to my past record with crappy mechanics, I'm afraid that someone poked a hole or dislodged something with they were changing my oil. Or could a new batch of oil make it sound like this? I had them put in 4 quarts of Durablend. I honestly can't remember how buzzy the engine was a year ago when I first bought it, but I know that last time I got an oil change, there was no change in the tone of the car. Now I don't know whether to take it back to them since they are not true mechanics, or to take it to the dealership.