"Joke post" or not - The best monitoring I've ever used were all "HiFi" speakers... All of them.
Except the Genelecs... Those were quite good.
But everything else - and not just for mastering (where you almost *always* find audiophile HiFi gear).
Certainly, most "off the shelf" bookshelf speakers at BestBuy aren't going to cut it. But there are many - B&W (602's, 805's, so many more), JBL (S-38's), Sonus Faber... The list would go on and on.
Just because something says "Studio Monitor" on it doesn't make it "flat" or "accurate" or anything else - It means that there's a sticker on it that say "studio monitor." And just because something *doesn't* say "studio monitor" on it doesn't mean that it's *not* relatively accurate.
Of course, the room is going to play a huge role in any system - But I've always switched over to the "studio monitors" just to see what the mixes would sound like on small, crappy, narrow-dispersion, short-throw, limited range speakers. I did the rest of the work on the speakers that actually sounded good. In a poorly treated room, I suppose I'd actually *want* short-throw, limited range, narrow-dispersion boxes (a.k.a. "nearfield studio monitors"). But in any case, I'd rather just fix the room.
At the original post - Changing the connector on a speaker doesn't do anything but change the connector. And not to "assume" anything, but if the speaker has built-in wire coming out of it with a plug on the end, it's probably not the speaker you're looking for. The only time you really see that are with really crappy "kiddie stereo in the Brady's Rec Room" stuff. Usually...