Even though the dialogue in the Campaign suggests otherwise, the newly acquired upgrades are automatically retrofitted in previously manufactured vehicles. ^[1]

Walrus & Manta

• Volcanic upgrade
• Icelands upgrade
• Marshes upgrade

Walrus

• Turbo

The Turbo module boosts engine output, causing an increase in speed for a short period of time.

Manta

• Afterburners

The Afterburners inject fuel into the Manta's exhaust, increasing speed for a short period of time.