For 150 you could take a unit of vets with 3x Gl's and an AC or HB in a chimera. This unit would be more durable and more versatile whilst still doing the job that the chimera and 3x HB's would do and only being 10 points more.
True that there more bodies & more flexible than the HWS... But that said unit combo cannot shoot further than 24" + 6" (vehicle movement) which is what I believe Land Rover Tangi is trying to get at with mass hvy weps.
Other than that though, I think Bobby P's idea is probably better for a mobile mech firepower unit. Being able to fire snapshot does not necessary mean that it would make our HWS any better at providing mobile firepower. If I am looking for mobile firepower, I would take a look at spec wep squads with 3 GLs myself. They are cheaper & can get the job done. (Plus 2 units of them only cost about 100 pts in comparison to the said Vets)
In my opinion, snapshooting is only a desperate option/move. It is often better to give HWS a good position so that they can ditch out lots of firepower over the course of the game. In this 6th edition, moving them (or a part of them) & having to snapshot should be treated as a defensive maneuver to avoid possible enemy assault
. That or move the HWS into a better position for shooting as a part of offensive strategy
when the enemy decides to hide or play defense.