In the vintage car world, we break things into 3 categories:
- showroom stock
- personalized
- modified
The category that aligns with your Hifi world depends on your "what does it look like when it is finished?" answer. Your personal commitment and resale value are major factors here. The most popular car catagory is "personalized." When upgrades are completed, you keep all the old parts and bring it back to "showroom stock" if needed. Cutting sheet metal is an instant disqualifier of (reasonably) returning to original. Thus is.whacking away at a chassis or speaker enclosure.
We’re with @audioman58 on the subject of "getting things out of the way that make it sound worse" mentality. Our philosphy for the least intrusive, keep "everything" there that the factory put in the box" is to look at connection methods and connectivity. Remove spades and lugs, direct silver solder, and bypass PC traces on the board with point-to-point wiring (if applicable). We’ve also learned that cables have a profound effect on SQ -- even short runs of 12" -- or less. You picked your amp --> speaker cables after intensive listening sessions and learned that various speaker cables sound "different." While there is a good chance that the internal cables are high quality, they may not align with your concept of what "high end" speaker cables should sound like. So, replacing those cables with your concept of the ideal cable (or close to it) can be a game changer.
As a "modder", our goal is not to "paint a mustache on the Mona Lisa", but deliver the sound that is characteristically "as the designer intended" IF the designer would have had the time, budget, unburdened from in-field service considerations, applied "newer thinking", etc.
Good luck.