Rated 3 out of 5 stars

In thunderbird 5 on XP:

The memory usage jumped from 120K to 240 K using this extension. Please fix.

This review is for a previous version of the add-on (2.6.0). 

Thanks for your note. Please file a bug on this using the bug reporting system on the addon's website. That way we can carry on a conversation and I can get more details.

PS - on my XP/TB5 machine Task Manager shows, just after TB start up 76,236K with the addon enabled and 67,084K with it disabled. So something is (a) making your TB install considerably larger than mine to begin with and (b) ThunderPlunger itself is unlikely to be the sole culprit here. So please file a bug report or send email (click on my name on the addon's page to do so) and we can explore the situation in more depth. This is just not the place to do it.