I’ve noticed there aren’t that many ‘rare’ things in this game. While I do support your idea, and the thruster part seems very interesting, though I have my special twist to it. Then again, I don’t want to ruin your idea, but here it goes -
Pretty much the thrusters should be found individually in science/military bases, so that would greatly add to their actual rarity, and then requires a high mechanics or electronics skill to combine into, say, thruster pack or something.
BUT. Each thruster pack has a limited weight capacity. As in, if your vehicle exceeds X weight, it cannot be lifted with a thruster pack and requires additional ones. + They need electricity/fuel to run.
Why so rare? Because they could avoid things like mines, rough terrain, use of wheels and travel via water. (Water bases?)
Okay, I know this is going seriously off-topic to your idea, perhaps something of this could be of use, don’t know. Random spur of imagination, I guess.