Yep, that is an S-mod slot if you really want it. I'd rather bring 2 oxen though and leave it at that. As is, the Apogee has plenty going for it and I don't miss it being the most optimal choice. I actually like how you have to, at least to a certain extent, balance things between speed, supply and fuel consumption, exploration, salvage and survey efficiency.
I just so happened to skim to your post-
Using an S-mod on a cruiser for ADF has two issues. The first and least subjective is that you only get 25% or so bonus exp for spending that stet point - you’ll only get the other 75% once, if, you scuttle the ship. Which is a bit of a downer, I like spending story points for maximum bonus exp when in the early game.
The second, it just feels bad using Smods on purely logistic Hullmods on ships that use up combat DP. that’s a smod slot that could have gone to anything else more exciting.
Both above issues are fixed by getting 1-2 ox and smodding it to have insulated engine and efficiency overhaul. You get 100% (or was it 75?) bonus exp immediately and you’ll probably keep the ox until you give up the save, anyway.
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One issue I have with ox is how they interact with the 30 ship limit. I wish we had like, 5 slots for civilian ships to slot into that ignores the 30 ship limit.