Re: upgrades

Yes, they are all real though the later ones make much more difference than the early ones.  Some - like health, ammo, damage and reload - are obviously quantifiable.  The health regen upgrades that you get first aren't particularly noticeable.  Try out default rose with homing, damage, and zoom upgrades, or a chomper with damage and two digestion upgrades, and you can't help but notice it.  Here's a chart of the different upgrades for all classes (though I feel like I've seen one that was more complete):

https://www.reddit.com/r/PvZGardenWarfare/comments/4bx592/upgrades_list