Agree with everyone else. Keep the 5 channels absolutely! I too run 5 channels like you but mostly listen in 2 channel. But every time the wife and I watch a movie we really appreciate those surrounds!
How about this; add 2 more REL subs? I run 4 SVS’. And whether it’s movies or 2 channel those other 2 subs just added so much more to the experience. I’m not familiar with the Elite unit and whether it has 2 sub outs (via RCA), but if not I would agree upgrade the Elite unit to maybe a Krell Foundation 4K and 2 more subs. This is assuming you would use the RCA and not XLR for your subs. I’ve always gone RCA with my subs..