I just bought my S4 a couple weeks ago, still trying to find out if some of the "symptoms" I'm seeing are normal or if something is wrong.

The car seems sluggish below 3,000 RPM. I know the sweet spot seems to be between 3,500 and 5,000. But is it suppose to be sluggish below that? It feels as though the engine is getting starved or it's hauling a 1,000 pounds behind it until it hits that magical 3K.

Anyone have any suggestions? It's at 85,500 miles.

It does have a K&N filter with intake and an after market exhaust (not sure what kind). Would those add-ons require a chip or computer re-calibration?

Thanks for the help guys!