I heard in the last order 66 podcast that you can push up your signature vehicle up to 7

As FFG is unable to deliver books to my local distributor since a whole month already … need a picture to decide if we need a rigger + modder.

Don't have a picture handy, but yes, between the two trees you can get up to 7 for your signature vehicle.

Here it is. https://community.fantasyflightgames.com/topic/206399-marcy-has-special-modifications/page-8