If that were the case, then dirty unfiltered air would have been getting in. Could have got the MAF dirty as well so you might want to go ahead and clean it. But I wouldn't think that the air bypassing the filter would cause the car to jerk and shudder, as well as give off the gurgling sounds you were talking about.

 

I have no idea. It's weird how when I put the unit back on, tightened everything, it runs more smooth, no jerking, no gurgle noise, and the power is back. no rough idle either.

I'll try cleaning to MAF soon to see if that improves it even more.