I have the vehicle sounds nearly complete. I asked people back ten months ago if they wanted an incomplete sound pack and they responded more positively to waiting until the entire thing was finished. It is a ton of work, not like the old sound packs (my first release took 3 years to make). This will make things a lot more realistic; like night and day different.
It's not hard to do if you know how to make your own sounds, modify sounds, and can follow the directions. I even made videos about how to do that.