Advice on rear speakers

xterra77
xterra77 Posts: 47
edited February 2008 in Speakers
Hi Guys
Current setup is
RTi10 front
CSi5 center
FXi5 surrounds
CSi3 rear (1 month old)
I would like to go with a 7.1 setup,I have a chance to purchase the last CSi3 (150)for my other rear or the last RTi8s(400) do you think therti8 will be ok for rears,or am i just wasting them.
tks.