sierra tower, sierra 2ex or sierra duo

[rysher]

since my piggy bank is almost full as you see in the pic, i plan to upgrade my whole system (tv, surrounds, amps).
i already got a TV to replace my 7 year old POS samsung and the ne step is to upgrade the L/R sierra 2 to either sierra tower or sierra 2ex or sierra duo
is there a noticeable difference between the tower and the ex?
i have outlaw 12 dual subs to handle the lower end.
i plan to move the sierra 2's to the back as surrounds making the system into 5.2

ascend.jpg

thanks for the help.