[Spaceships] Paying more for better system?

[PTTG]

Here's my take:

TL8 spacecraft are built on such thin margins that worse equipment than standard is a collossal risk, and better equipment is exceedingly hard to find (at least in space-hardened grades). In essence, an upgrade significant enough to warrant a change in statistics calls for paying full price for an upgrade to TL9. And that's before you consider that most spacecraft are bespoke.

At higher TLs, spaceflight is developed enough that there is some variation in available tech. At TL10, only cutting-edge ships are made exclusively with TL10 components. Many ships use TL9 variants. They might be extremely recent designs, but they have essentially the same performance as they did in the previous tech level.

All of that said, as a GM I would still throw in the option to buy cheap, refurbished, or poorly-maintained ships which are statistically the same as others with the same loadout. The difference is 10% or more off the top, with the addition of quirks.

Said quirks could be anything from "The cargo holds are awkwardly shaped, take a -2 to orders to load or unload quickly," to "The reactors on this line were always tempermental. After any severe shock, roll HT to see if the cooling turbopumps jam." The discount probably varies more according to the personality of the seller than by the severity of the quirk(s).

[jacobmuller]

I borrowed a bit from 3rd edition Ultra Tech, etc and put Build Quality guidelines in my Spaceships House Rules.
If it saves you time...
Build Quality
Overall build
• HT±#, Reliability, HT bonus, +1 for +1 CF, +2 for +4 CF, HT penalty, -1 for -¼ CF, -2 for -½ CF.
• H±#, Handling, +1 for +1 CF or +2 for +4 CF; -1 for -¼ CF, -2 for -½ CF. Spaceship Limit ±5.
• S±#, Stability, +1 for +1 CF or +2 for +4 CF; -1 for -¼ CF, -2 for -½ CF. Spaceship Limit ±5.
• RB±# Styling: Reaction Bonus +1 for +1 CF, +2 for +4 CF, and +3 for +9 CF; Reaction Penalty -1 for -¼ CF, -2 for -½ CF.
Individual systems
• TL: Cutting Edge, performs as TL+1, CF+2; Experimental = TL+2, CF+9; eg drives get more δv, power-plants run longer.
• Quality: Good-Quality, Gives +1 to operation skill, or adds +1 to existing modifier +4 CF;
Fine-Quality, Gives +2 to operation skill, or adds +2 to existing modifier +19 CF.

[weby]

There are no special official rules for Spaceships on the improved things, but I think you could use the generic GURPS rules for better/worse equipment(things like Rugged, Expensive, Fine, Very Fine, Cheap and for computers all computer modifiers) and not break anything.