Tech wizardry simply increase damage done from tech attacks by a certain percent.

But armor penetration is more confusing to me. Suppose someone's armor gives them 20% damage reduction against kinetic attacks such as laceration, veiled strike and backstab. Will a 2% armor penetration amplifier reduce that damage reduction to 18% or will it reduce it by 20% multiplied by 2% which is 0.4% making damage reduction 20% - 0.4% = 19.6%?

If that's the case then shouldn't tech wizardry be superior to armor penetration or does the cumulative effects of armor penetration eventually surpass tech wizardry?

Say that out of my nine pieces of equipment I have 1% max tech wizardry on each piece which adds up to 9% in total. Compare that to armor penetration - say I have 2% armor penetration on each of the nine pieces of gear - I would have 18% armor penetration.

Going by my previous example if I had 20% kinetic damage reduction from armor with an armor rating of 6825. Amplifiers with a total of 18% armor penetration would neglect 18% of the total armor. So I would only count 6825 * 82% = 5596 armor rating. If I remove my pants I get 5425 armor rating which gives me 16.74% damage reduction against kinetic damage.

So basically tech wizardry can provide more damage than armor penetration if the above example is true because 9% more damage is greater than 3% more damage.

Going on my tank spec Jug I have 18111 armor rating that gives 40% damage reduction. WIth 18% armor penetration it'll render that armor rating to 14851. If I remove my pants I have 14815 armor rating and that reduces kinetic damage by 35.45%. So in total that's a decrease of 5.5% damage. So tech wizardry in theory should still increase damage more than armor penetration even when taking into account high armor classes.

According to Smarty and crew, these are the bonus damages (excludes any tacticals or opponent defensives).

[b]Concealment / Scrapper Damage Increase by Amplifier Type[/b]
Weapon Expertise: +0,11%
Tech Wizardry: +9,31%
Armor Penetration: +5,34%
Periodic Intensity:  +2,36%

So yeah, Tech Wizardry all the way.

But I'm actually curious about raid bosses. I wonder their armor is? And at what armor rating will Armor Penetration be better than Tech Wizardry?