Really, if you send LAV-75s with ATGMs you don't need to upgun the ARES turret.
(By the way, the ARES turret is really modular. There's lot of images of it mounted on Stingray, M551 and even M8 chassis)
Here's a site with many images, although it's a wacky group associated with the infamous 'M113 'Gavin' Sparks'