Tech has three levels: [Prototype] (+25% Cost), [Standard], and [Mature] (-25% Cost). That gives you incentive to pick mature tech because it's cheaper.
[Prototype] techs become available when the previous tech becomes mature.
Technology ages over time, transitioning from prototype to standard to mature.
Installing prototype technology accelerates the transition to a standard tech in X years. Very successful ships accelerate it substantially because of all the experience crews and technicians get. Less successful ships, less so. Testbeds are nice, but nothing compared to prolonged operation.
Prototype tech has a roll attached for its effectiveness. If it fails the 50% chance(?) effectiveness roll for rushing the tech, the improvement is reduced by 25% for that class until the technology standardises. But you still get the progression towards the change to standard tech, so that malus will disappear when the tech is fully standardised.
My feeling is that strikes a balance between incentive (better stats, faster tech progression) with risk (higher cost, lower performance increases). My sketched-out table looks something like this:
Component | Implementation | Cost | Real Cost | Effectiveness | Unknowns | If Taken | Implementation Schedule |
Duratanium Alloy Hull | Standard | 3 | 3 | +60% Defense | | | Mature: 2260 |
Type-3 Impulse Thruster | Standard | 5 | 5 | +50% Thrust | | | Mature: 2260 |
Type-1 Photon Launcher | Mature (-25% Cost) | 3 | 2.25 | 6 Average/18 Burst | | | Tech Matured |
Type-1 Rapid Launcher | Standard | 12 | 12 | 18 Average/54 Burst | | | Mature: 2260 |
Type-2 Phaser Bank | Standard | 4 | 4 | 18 Damage | | | Mature: 2250 |
Hull costs remain the same, while protection increases linearly.
So from reading the table you might reasonably say something like "well this isn't a combat ship, but even a minor adoption of the more expensive hull plating will make sure it's available as standard for the next project". Or "the thruster is too expensive for a ship that doesn't need it and I'd rather lose twice the space to engines in future builds than pay more than double for the next couple of builds - or save it for a ship that needs the thrust".
EDIT: If anybody observes that better tech is more expensive than older tech value-to-effectiveness, that's deliberate. The Intrepid/Nova/Sabre-class didn't get the same grades of shield as the Defiant/Sovereign/Prometheus, despite being built in the same window.