Well, as I said. It's a pretty complex topic so I'll try to answer your question as good as possible with links related to current research.

While caffeine is generally metabolized by a one specific Enzyme of this CYP P450 family (CYP 1A2 to be exact), Naringin mostly inhibits CYP3A4, which belongs to the same Enzyme-system but is part of another subfamily. Thus the effect of your coffee should probably not be significantly increased.

I just searched for some studies who were looking into this and found this.

Feel free to take a look into it.

General description of caffein including the metabolizing enzyme
Studies researching a possible interaction 1 + 2
Studies about the pharmakokinetics of grapefruit juice including some drugs it might interact with (This is not a complete list.) 1 + 2
Don't think every other medicine is save to combine with grapefruit juice. The best thing to drink when you're taking medicine still is simple water.

All in all I doesn't seem like combining grapefruit juice with coffee seems to have a significant impact on the caffein in your blood.

It's like the extra robots are chasing some of your IT-specialists that are mainly experts for one OS but leaving the other ones who are responsible for the "caffeine"-bots' OS do their work in peace.