what happens if you dont get the necessary upgrades

[Imminentpulse]

if you dont get the necessary upgrades, does your allies die or live?

[stokroc1]

in a very bad ending everyone from team will die (including Shep). Only Joker will survive

[Kenny32673]

Certain people will die if you don't get the three ship upgrades yes.

If the Thanix Cannons are installed, the Normandy SR-2 uses them to successfully destroy a Collector cruiser guarding the Collector base shortly after passing through the Omega-4 mass relay. Otherwise, the Normandy will attack the enemy ship with her conventional weaponry at extremely close range, but will sustain severe damage as a result; a crewmember will be impaled by a metal beam, resulting in his or her death.

The Kinetic Barriers prove to be useful during the final mission as Joker maneuvers the ship through the debris field. Otherwise, collisions with debris may cause the ship's power core to overload and explode, killing a squad member.

If the Heavy Ship Armor is not installed, an Oculus energy beam may penetrate the Normandy's hull, instantly killing Jack.