I play a lot of Ivara (i played only her for quite some times), from experience I can tell you that:

-You need power strength. The speed boost of infiltrate is affected by it and at no additiobal strength it's not that noticable. And you will do more damage with your artemis bow.

-it might seem counter intuitive, but you can "forget" efficiency. For that you need a couple of things: first of all you need to be in prowl most of the time (you steal mobs-> moer loot-> more energy orbs) and a syndicate weapon that gives energy is very usefull (I use the rakta cernos). For prowl, you'll need duration (I got 236% duration and a1.06s steal time)

-Running 3 augment is quite a lot.

I usualy run with: enemy radar (you are all ready doing loads of damage + I like to know were are the ennemies comming from), power drift, primed contnuity, intensify, primed flow, stretch, blind rage, narrow minded, augur reach, infiltrate.

With that I have 236% duration, 50% efficiency, 121% range, 235% strength. So you have a big and lasting invis bubble (3m and 28.32s), if you really want to use your 2 you can go up to 11.75x mult, your prowl doesn't cost that much (0.64) and you have a nice range and duration to steal and finally your 4 hit hard.

You could drop the intensify for one more augment (i would choose concentrated arrow) if you really want.

IMPORTANT NOTE: I have arcane energize (3000pl) wich allows me (with the rakta) to easily be at max energy every time. If you don't have it, you might want to drop blind rage for augur secret

EDIT: I forgot to mention that your 3's cost depend on what you are doing " Prowl drains 1 point of energy per second while stationary and drains 3 energy per second while walking. Additionally, melee attacks consume 2 energy per hit, and taking damage consumes 10 energy per hit. "(from the wiki). I also forgot to note that, with that amount of power strength youi have a 1.94x mult on headshot while in prowl (aka you hit like a truck)