Is it possible to have stats like health,mana,steagnth etc ?

Sure
But a lot of code is required to add anything to SigGen

Add a few lines to siggen.php
And if you want any type of control to it, add a few more lines to templates/sc_body.tpl

I have been slowly working on a new version that will make this as simple as clicking "add text layer" and typing "[Health]" into it
Currently with work on the Roster 2.0 beta, coding it is a slow process and only at the "initial concept with some small bits of code" stage