So you can upgrade shipcomponents.

Can you upgrade everythign else as well? Can I upgrade my Power Armour to "Best-Quality"? Or gun or whatever?

The crafting rules from inquisitors handbok could be used for tha. If you do use those, the answer is yes you may upgrade equipment but only by one step.

Graspar said:

Or just make use of your vast wealth to buy new equipment of a better quality. That way you also have some gear to give to a favoured subordinate.

The real difference is that having a 'Best' munitorium has no real effect on the game.The GM might let you find a better cache of weapons if you need to raid the stores, but it's entirely at his approval.

A 'Best' gun on the other hand, has clear figures. It never jams or overheats. Best armour weighs half the amount, and provides 1 more ap.

Also, when you say 'You can upgrade starship components', what exactly do you mean? The only thing I've found in the book covers the time and facilities required to install a new component, it says nothing about turning one component into another. Likewise, the only rules for upgrading a weapon is installing an upgrade component (E.g. Scope).

If the GM is willing to let you, then Trade: Armourer for weapons and Trade: Shipwright for ship components would be the skills to use, but I'd disallow it. A beter quality item in 40k means it's a relic, made using ancient technologies long forgotten. Even if they do know how to make the things, it has a much higher production standard. Casings will be hand-finished, screws carefully measured and moving parts made entirely by hand. The whole thing will be made of superior components, designed to last longer.
A common gun is mass-produced for guardsmen, to a quality deemed 'good enough'. A Best lasgun is hand-crafted by an experienced tech-priest. They have a common shape, but no common components. Upgrading a weapon means replacing everything.

As far as I understand the rules 'upgrading' a shipcomponent actually means to replace a component with another most likely better one.

Off course if you and your GM both agree, you might rule, that a formerly unknown part of a tech-device could be activated by some actions. I could imagine, that by adding some newly aquired augurs to a macrocannons targetingsystem could improve the quality from common to good. In game-rule-terms I would still ask for the same rolls required to get a completely new item of the new quality.

On the other side I don't see any sound way to 'upgrade' an armor's quality from good to best, since it would take a complete rebuild of the whole armor to reduce it's weight by half.

So I would advise: Talk to your GM (or players) and use some common sense to determine how you would like to handle such ideas.

Regards,

Nadomir