Thanks for the info.
Looks like a gain of 10% for Damage and 5% (max 24%?) for Shield between A-class and S-class Fighter. Would be nice to see default values for Maneuverability, but it seems like S-class Fighter equals this value with an Exotic.
All-in all, I think it’s worth trying to find an S-class fighter at some point. It has the ability to outperform an exotic on all fronts, besides hyperdrive, therefor leaving warping for exotics (or explorers).