The Levels plug in by Mastering the Mix company looks interesting....any thoughts?
THanks.
 

I don't own this plugin but I use all those metrics when mixing.

I use RME DigiCheck to read the levels of all these metrics. European broadcasting union 128 meter... crest factor etc.

I use them for every single mix I do.

https://www.masteringthemix.com/products/levels

This is the plugin I looked at. The low end spectral analyzer you really already have in sonar platinum.

A bit of money for this.  A decent VU meter will get you about 75% of the way there. There are free loudness meters and DR meters around as well.  Span will tell you what is going on in the bottom end of your mix and it is free too.