I used to raise peak levels in Audacity to just under -0.2dB peaks using the Amplify effect, but now I use hard limiting and sometimes even multiband compression in Digital Performer.
Can you elaborate on what exactly you're doing when using these?
Barely. I'm just learning but my buddy digtalist0ne has some tricks in his sleeves, and I'm starting to get the hang of it. All plugins sound different, so make sure you actually like the ones you're using. The Masterworks limiter & the multiband are adequate, but it would not be unreasonable to spend thousands on software to emulate classic gear costing hundreds of thousands!
While most mics spec from 20Hz to 20kHz, they actually pick up and transmit frequencies well outside that range in most cases. Which, if only in perception allows for those beyond human hearing frequencies to be accurately filtered off when sampling at such a high sampling rate.
some people can hear beyond that too. Wonder if your bandpass limiting is audible to them? If we get bionic ears, or direct brain implants, you'll want that stuff back, so save the masters!