I think someone else was playing one against the other.
It does come down to "it depends", frankly, it really hinges on what you want & what you're going to mod.
SSV-R comes with better speakers & sub, sunroof, grille, brakes, suspension & wheels; except wagon doesn't get the stereo or sunroof stuff. There's other minor stuff but I don't think anything else worth mentioning. By late VF2 the seat differences were minimal.
Calais V comes with more interior trinkets & toys.
If you were going to tweak suspension & wheels, and were getting a wagon … really only the brakes & fugly Calais grille differentiate them, except the Calais does get the trinkets (can't recall what - heated seats? Seat memory? Electric passenger seat maybe? Puddle lights?).