[Rich Breen]

As others have pointed out, further processing after a lossy conversion should be avoided at all costs - lossy conversion should always be the last step before delivery if required.

Insight is a metering plugin, not a processing plugin. While a good set of meters will provide important information about overall levels/peaks/etc, you need to set relative loudness by ear, and peak/rms normalizing is both unnecessary and ineffective for this particular task - a good limiter will be required if you're trying to reach commercial delivery levels; Izotope's Ozone, Fabfilter Pro-L2, DMG Limitless, Nugen's loudness suite are all good products, but you can do more harm than good with them (particularly Ozone) if you don't know what you're doing.

I think you need to learn more about the basics of digital audio (starting with the difference between various formats); I'd start with Bob Katz's "Mastering Audio".