A Space Range weapon or sensor will still be Space Range after reducing the range. Note the separate Range Effects tables for Space Range and World Range systems.
The fighter is far more capable, as it can operate as a separate spacecraft.
Not by RAW, you would have to house rule it. By RAW we don't even have a system for building small craft.
I do understand the relationship between space range and world range, and that S = R - 5 (from memory, which may be faulty.) I mentioned page 53 because of the "A Firmpoint will accept any mount which is less than one ton ...
and contains a World Range Weapon, Defense, or Sensor." quote.
My biggest point was that a deployable turret is at 3 dTons, and is treated as a FULL NORMAL hardpoint; even when deployed it loses no capability,
retaining its full size, range and power. In that regard, it is a VERY short-ranged 3-ton fighter. [Remember that the deployable is usable as a life pod, per T5.1 page 156.]
So, why does size NOT matter when deployed, but DOES matter for the pod hull/small craft? That is the issue I want to resolve.
I actually use the ACS rules to build small craft. Others here (Robject included) have also showed how to use the ACS rules to build small craft. Personally, I think that is the reason "pod hulls" were included in T5 to start with, though that is solely my opinion without a definitive YEA or NAY from the powers that be. IMTU I don't distinguish between FP and HP when I deal with small craft.
I do understand that firmpoint vs hardpoint is the RAW, and "because Marc said so" applies, but that "intersection" still exists between the firmpoint <-> deployable mount <-> hardpoint, which does not sync with the entirety of the FP vs HP issue.
In any case, the discussions in this thread have been interesting, and like all things Traveller, to each his/her own.