Are delivery vehicle upgrades purchased at a warehouse permanent?

[Daddy Gibby]

When I go to that workbench thing in my special cargo warehouse and purchase all the vehicle upgrades, are they permanently applied for ALL future deliveries, or do they need to be purchased again after each delivery? And when purchasing them, I have to do it for each individual warehouse because it doesn't apply to all warehouses correct?

[Koby]

They're permanent and work for ALL your warehouses.

[Jaq]

Unsolicited advice: Only the airplane armor and tugboat speed boost are worth it.

[in]

Originally posted by Jaq:

Unsolicited advice: Only the airplane armor and tugboat speed boost are worth it.

Bp tires for trucks is also nice.