They don't have scanned models free sample, so i downloaded this
texture, which is also scanned, so should be good indicator on their texture quality. To be honest, i found nothing wrong with those textures - once you plug them in material, it works as expected. No need to boost anything, well... maybe except glossiness. That map is good by itself, but it's for dry mud and in their preview, mud looks wet, so if you want to replicate that, you need to make that map lighter. CoronaColorCorrect node is perfect for that. One thing is worth to mention, they also provide reflection map, don't know what's its purpose - i didn't use it. Instead i plugged into reflection slot AO with boosted contrast - nice trick advocated by dubcat and Juraj Talcik.
I'm attaching test renders.
01 - maps are pluged without any modification (AO and reflection aren't used)
02 - glossiness map is plugged through CoronaColorCorrect and brightness with gamma are increased
03 - same as 02, but high contrast AO is plugged into reflection slot