The only 'mods' for this kit was the 'beam sniper system'.  I theorized that if the storage container on a RX-789(G) could hold litterally tons or weapons, why not a second low end reactor to power the beam sniper rifle. Although originally I was going to scratch build a reactor for the inside of the storage container, the kit was already back heavy with the sniper rifle mounted on the clip on the side of the storage container, so I decided against it.

The practical considerations for this kit are as follows:
-I mounted a clip to hold the rifle on the side of the storage container. This allows the model to do an 'over the shoulder' draw, shotgun style. 
-I modified the right hip armor ammo clip to act a a guide for the power cables running from the storage container to the gun. This would prevent the cables from becoming tangled.
-Then I ran the power cables from the rifle , thru the right hip guide, and into the storage container where the reactor would be housed.
-Finally, due to the 'beam sniper system', the MS would not be able to access the beam sabers in the legs with the sniper system mounted. So I modified the left hip armor to mount a single beam saber that could be quickly drawn by the left hand if the need arose.
-Lastly, the entire 'beam sniper system' , can be abandoned by dropping the storage container and ejecting the right hip ammo clip.  Making the system completely modular.