Go to my site (
www.pmulcahy.com) and look particularly under Russian Tanks. I think I did a decent job with systems like Drozd and Arena.
As for ERA, they're in the v2 and V2.2 rules, as well as in the V1
Soviet Vehicle Guide if you need a v1 version of ERA. You might also go to my site, look on the PDF downloads page, and (hope you have a high-speed connection) download Wapahani's (TR's) site. He had some good rules on more modern ERA systems.