@Vyndicu:
I tend to view the Spire Corvette as either a stripped-down (and somewhat improved, in some ways) version of the Spire Starship, which makes use of the greater understanding of Spire technology resulting from contact with the Imperial Spire to allow the mounting of Human/Spire modules, or as a Spire Frigate enhanced with human technology resulting from the development of the Spire Starship and modules for the Imperial Spire warships you can get in the FS campaign. The description of the ship indicates more that it is a stripped-down Spire Frigate outfitted with extra human weapons, but its statistics look more like a stripped down version of the Spire Starship, and the modules are the same kinds of things you can mount on Spire Destroyers or other larger Spire warships (I haven't checked the statistics of the modules, though, so it might not have the same modules, just the same types of modules).
Also, the Spire Starship isn't really a Human/Spire hybrid (although possibly we could argue that the newer iterations of the Spire Starships are, with the old versions representing the attempt at imitating the unspecified artifacts in its description, and the enhancements made representing contact with the Imperial Spire granting greater understanding of the technology that the Human factions attempted to replicate, and possibly some direct technical assistance from the Imperial Spire). It is more an imitation of what the humans thought the Spire technology was based off of unspecified artifacts, or a result of attempts to reverse-engineer Imperial Spire technology based on derelicts, debris, or other things like that, rather than a concerted effort to mesh two technology bases. I'd say that the Spire Corvette (and arguably the modules you can add to Spire Destroyers and higher) represents the first real hybridization of the Human and Spire technology bases, with both factions being involved in its development.
The above, however, is just my view on this.
As for where the Corvette fits in the ship line-up, I'd put it between the Spire Frigate and the Spire Destroyer/Starship in size and power, despite its name indicating that it should be smaller and weaker than the Spire Frigate. Perhaps consider the Spire Corvette as a Battlecruiser while the Spire Starship is a Battleship - ship types with similar damage potential (that being "lots"), and one trades a lot of durability for a slight speed advantage (in this case it's more a trade-off between firepower and durability, since although the Corvette does have a very slight speed advantage, the difference is mostly in its module-based firepower and lower base health).