The notion of fitting Balls with leftover GM equipment seems like an obvious non-starter. Unlike the situation with the Oggo, the Federation didn't have
any leftover GM equipment; if it did, they'd just give it to GMs.
As far as the Ball's performance, it would presumably be outclassed by a conventional space fighter in terms of straight-line acceleration and speed. (That's why space fighters are better for hit-and-run attacks.) And it can't really do AMBAC maneuvering, either. But the main advantage of the Ball is that's it's studded with verniers; in older sources like Gundam Century, the Ball is the only
machine that's specifically cited as using attitude control verniers, and even with recent retcons the Federation's other mobile suits haven't sprouted as many verniers as their Zeon adversaries.
Given that the Ball is covered with verniers, it may actually be surprisingly nimble in close-quarters fighting. I kind of get that impression from MS Igloo too.
Speaking of which, the MG kit actually provides some whimsical back story for the Ohio team and their "sharkmouth" Balls. Apparently they fought at Solomon, and survived the destruction of their mothership Naganuma when it was blown up the Elmeth's attack on Konpeitoh shortly afterwards. Then they ended up at A Baoa Qu, bearing witness to Gato's Gelgoog as it hacked through GMs and Balls. I guess they were just off-camera during the opening scene of Gundam 0083.
EDIT: I checked Gundam Century
, and it gives the Ball a 180 degree turn time of 2.2 seconds - only fractionally more than a Guncannon or Rick Dom, and substantially better than a Zaku I. Since these mobile suits are supposed to be way more maneuverable than a traditional space fighter, that's pretty impressive for a non-AMBAC machine!