Well, I guess everyone has an opinion, but I'd much rather use an SLR than a Superlative; Odin is my next choice, but they can be an issue with some small ID handguards.

As to what to change 1st (w/o an AGB), again, IMO, assuming full weight M-16 BCG, then buffer first, spring 2nd (depending on where you started, I always start with Sprinco standard white or slightly enhanced blue) and gas port size change is last.

Here are some nominal gas port typical sizes.................check yours to see if it's close to something nominal. Scroll down to the 300 BO data.

MM

Typical Gas Port Sizes