Is There A Big Difference Between Subwoofers From Different Manufacturers

This is likely the last thread I’ll be posting about subwoofers.

I was just wondering if there is really a big difference between subwoofers from different manufacturers if the quality of the subs (which is mostly governed by the specifications) are fairly similar. Also, with the assumption that the set up is properly done to ensure a seamless integration with the main speakers.

There have been many comparisons or experiences on subwoofers shared by members here on this forum, people who upgraded their old sub to a new seemingly superior sub. Or people who added additional subs to the system which contributed to an overall improved bass performance. I’m referring to the former, the comparison between single subs.

To cut to the chase, I understand high quality subwoofers which are essentially higher spec designs will usually produce better performance than lower spec subs. When people upgrade their subs, I assume the new subs are superior in terms of specification, either a larger sub with larger drivers, higher power output of the internal amplifier, lower frequency extension or the combination of any of the above.

Has anyone compared subs which are fairly similar in quality or performance when upgrading from the old sub?

Example. If someone upgraded from a REL T7x to an SVS SB-3000 or SB-4000, I suppose the SVS would be an upgrade since they come with larger drivers, higher power output, everything superior spec-wise. What if the models are closely spec’d? Will the subs sound fairly similar or closer to each other ?

Say, the comparison between

SVS SB-3000/4000
Rythmik F12SE / F15
REL S510 / S812 / Carbon Special or Limited

I presume the subs will still sound slightly different but the difference may not be night and day if the quality or specifications are closely matched?