[Alfalost]

I have read numerous threads about a variety of vibrations, but I'm not at all clear any match the vibration I have.

I first became aware of it at a traffic light, and believed that it went away when the clutch was depressed. Therefore, I just spent a bunch of time replacing the clutch with a new Spec one. Also replaced rear subframe bushings, diff bushings, and transmission mounts while I was at it.

The clutch feels great.

The vibration is unchanged. The car idles smoothly. Around 2000 rpm, the vibration begins, and increases as rpm increases until it almost becomes a hum. It can be moving or at a standstill, in neutral or in gear. It isn't wheels or drivetrain, since it doesn't need to be moving.

Does this seem like an engine or an exhaust issue to you?