Yeah, sorry, standard disclaimer in case you broke it
Since you're running the Cool-er firmware you should be able to skin yours the same way I did with a genuine Cool-er - check out the link in my signature for more info.
As for the differences, I'm not really sure.
According to the wiki page the difference between eb600 and the eb600e/em is the epson display chip. I'm not sure what other differences exist between the e and the em.