The collision model on the Sath (for the turrets, at least) is HEINOUS!
I really noticed this when playing BP:AoA, actually, as getting rid of those forward flack guns is of upmost importance to your general well-being, especially in something like the Ursa. You'll not that "Trebbing" the forward flack guns from most forward angles is redundant as missiles/bombs will explode on the fixed barrels (amusing little low-complexity nitpick, there...

) rather than actually hitting the turret. This isn't a problem for guns, but unless you've got Maxims, you don't want to be around that madness.
The beam turrets are also bad (in terms of the collision model), but not as bad as the flack guns. Set up your bomb run forward and at an angle above (for the top beams) or below (for the lower beams) when making an attack. Also give yourself some space. The Helios has a rage-worthy tendancy NOT to lock when you're too close to your target, so though making some distance between you and the Sath may take some time, it's time well spent.