the outside unit largely sets efficency. new outer uits are much
physiically larger

thanks... now, that's what I'd really like to find out. If I use my
existing 10 Seer condenser with a 15 Seer indoor coil, should I expect to
get somewhere closer to 11 Seer, or 14 Seer, or somewhere in-betwen when I
mix & match like this?