Actually, on all the sales material that I've seen or been given, including directly from Embraer, they call it the EMB170... *shrugs*
<< from an e-mail from the Director of Sales >>
(See attached file: EMB170LR.pdf) (See attached file: EMB175LR.pdf)
<< end >>
Although this plane isn't quite a regional jet.
In regards to the engines, near same core, just a different, more powerful derivative...
~ ~ ~ ~ pRoFeSsIoNaL hUrRiCaNe DoDgEr ~ ~ ~ ~