Each turret, hull and paint with protections can be upgraded.
Thanks to Micro-upgrades, you don't need to wait until the next modification of an item becomes available, you can improve its stats step by step immediatly.
When fully micro-upgraded, M0, M1 and M2 modifications of turrets and hulls have equal parameters to their higher modifications. When you fully micro-upgrade an item, you will get its higher modification for free.
In order to start this process, you need to select an item in your garage and click on the "Upgrade" button. One item can have several parameters that can be upgraded all together. There are a total of 50 upgrade steps for each turret and hull. Once the process of upgrading has started, installing the upgrade will take some time. However, you can always skip this waiting time by clicking on the "Speed up" button.
NOTE: Weight parameter for hulls is disabled in Parkour mode.