I'm looking to purchase a powermeter, and I am interested in a crank version. In looking at this, it seems obvious that I need to decipher what I currently have for a bottom bracket.

My crank is a Shimano FC-RS500 compact crank. The lit on my bike says my bottom bracket is a FSA EVO PressFit 30 with Wheels MFG EVO adaptors. Does this mean that I'm looking for a PF30 compatibility or am I looking for FSA EVO compatibility?

The powermeter I'm looking for is not sold through my LBS, so I'm not sure I feel right about asking them for help buying something from someone other than them.

The powermeter comes in BB30, PF30, and BB86.

Which is right for me, and do I need a new bottom bracket based upon this availability? Really confused. I long for the days of English or Italian.

I would look for the BB30 version because that is a direct fit to your bike. (No adapter to potentially spoil the solid connection.) But I know little about power meters. Which models are most desirable, costs, availability, etc.