3.5/5 stars. Rounded up. Expensive, but the rules are good.
This is the Imperial Mole - a massive transporter that burrows underground. It can then emerge behind enemy fortification lines and disgorge its deadly content. Effectively a siege engine with its lineage traceable to terraforming activities.
With an impressive 42 person transport capacity, this super heavy mole will carry what you want. With 14 hull points, AV=14 on the front and 13 elsewhere, and subterranean assault, it will also carry them to where you want them to be without much danger of getting lost or blown up along the way.
There's also an interesting weapon that causes a permanent immobilization to create a short range "earth quake" of sorts. This pulses outward depending on the game turn and can grant pinning as well as hitting vehicles on their lowest armour value. Interesting to use late on if the Mole is in position.
The points cost is very large here, but it will certainly do its job. The firepower is distinctly average though.
There are no upgrades here, hence no build to discuss.