What color is the smoke?

Are you missing oil when you change your oil?

If it is a stock engine, it is highly unlikely it is running rich enough to cause smoke. Sounds like toasted piston rings to me.

The stock fuel pressure is not adjustable and putting an adjustable fuel pressure regulator isn't going to help the problem. You would need something to lean out the fuel ratios like a VAFC, but I find it would be highly improbabable that you are running overly rich.