Once the Mod-o-Tron quest is complete, mods can be applied to Parts. Cost of modding is 500 metal for each mod applied. Parts can be unmodded for 5000 (ingame saying 3k is wrong) metal in your collection screen, giving back all mods (at once) and the part. Cost for un/modding can be lowered by up to 75% with the Tuning Skill.
Scrapping a modded part will destroy the mod/s on the part!
The effect of most mods stack. Their effect is applied to the BASE stat on the part it is applied to - unless it states otherwise.
- Example: 3 Stripped mods (-10% weight each) on the same part lower the part's weight by 30%.
There are 2 Achievements connected to modding, though they only give metal so it's not worth specifically going for them, one get's them eventually when modding parts anyway.
- Strength: Mods not only add the strength shown in their details, but since str is the sum of stats, the str is higher when mods add to stats, a single Life III mod can add 20 str on a chassis with high base HP like Skyshark. Works the other way around too, the Baited mod is effectively -8 and not -2 str
- Damage mods: Since those mods only work on parts that have "## - ##", not "X - X" damage ranges and "hit", it is a waste to put those on, e.g. an engine or parts like LiForce Cannon, Ragna's Rok, The Interrogator or Suck-VAC. Only exception are a few chassis abilities that are affected by dmg mods, like Thermo Nuke.
- Weight affecting mods: Mods that affect weight should best be applied to the heaviest part. So put heavy mod/s on the chassis (e.g. Decker) to most effectively increase ram damage, same for stripped mods, since usually the chassis is the heaviest part. And you don't want to use Bertha on a Spam Hopper anyway. Note: Putting heavy mods on a part with negative weight (Dual Prop Engine, Shielded Tanks, Energine, The Rudy) decreases the weight further.
- Proc Mods: Those mods that have the chance to apply Effects. Since the chance is usually small (like 5%) they are pretty useless on a slow one-hit weapon like Kupos Cannon, but great on fast weapons that pulse often, like Flame Streamer or Jack Hammer. Still mediocre to useful on 1sec weapons/Spammers.
- In general most useful main stat to mod is HP, since some attacks bypass evasion (The Interrogator, Prowmaid etc.) and some armor (Plasma Rifle, The Interrogator etc.). And you can never have too much HP ;)
- Regen: To find out how much regen you need for a certain weapon, divide the energy used by the attack by your Piston Reset Speed + weapon action time. Then get the needed mods to get to the wanted regen rate.