I'm a little suprised this hasn't been discovered yet or posted, but hard counter units don't need to be upgraded in order to kill the other counter. It may not apply to hunters and grizzlies, but think about it.
Wolverines with no upgrades rape all air units. So unless your looking for a siege weapon of sorts or need to boost their combat efficiency then the upgrades are pointless.
Same with vamps. In fact upgrading them is reletively useless as they already have their stasis attack which is what makes them a great AA.
And cobras too
I am not saying that the upgrades are uselss, just pointing out that you don't really need to bother upgrading your cobs if your enemy starts pumping out tanks.
If you say PLZ because its shorter than please, I will say no because its shorter than yes.