@krispy It seems as though he's only affected by the modifications when he's transformed. Without partially transforming, he can't get any kind of boost. He's already tried partially transforming already, but as we've seen, once he starts he can't really stop, and ends up going all the way out of reflex.
If he could teach himself better control, he could partially transform and be superhuman without having to fully assume a kaiju form. But that might not be a great idea, since the suits they all wear send biometric data back to HQ. They would detect something like that, it would raise questions he couldn't really answer.