This is my [Pyrana Prime] build.

Both primed mods do make a big difference, 100% worth getting both (prioritize Primed Target Cracker)

You can consider swapping Heated Charge for the 60/60 Heat mod or for [Carnis Stinger], if you so desire. (slash damage isn't that great in the weapon so stick with heat xD)

If you are swapping Heated Charge for Scorch (60/60) make sure to swap [Jolt] with [Frostbite] for viral damage.

For rivens you should look for Damage, Multishot, CD, CC, and elemental damage, always get rivens that give you harmless negatives. (not worth buying godrolls)

Swap the mod slot of your riven according to the elemental damage you get.

If you get a riven with more multishot, you can consider swapping [Steady Hands] for [Targeting Subsystem] which will increase your accuracy while aiming (less spread)

if you get Electricity damage in your riven go for corrosive damage, it will work just fine.

You CAN swap [Heated Charge] for [Hydraulic Crosshairs] if you want the nice numbers in your screen, but i wouldn't recommend it.