If you want to use Emacs and SLIME with Opusmodus, that is possible.
Here are steps that work:
If you haven't already done so, install Quicklisp.
Evaluate (ql:quickload "quicklisp-slime-helper"). Follow its instructions and put
(load (expand-file-name "~/quicklisp/slime-helper.el"))
into your ~/.emacs file.
Start Opusmodus, and evaluate (cl-user::start-swank). This should print something like ";; Swank started at port: 4005".
Now, start your Emacs. Ty