[plt-scheme] Easy module switching?

Hi, I was wondering whether there is an easy way to switch out certain
modules for alternate ones. For example, I might want to use different
versions of a debugging/contract library depending how much
performance/debugging I need at the time.

I was wondering about using a command line option to require a file
which did something funky with current-library-collection-paths, but
I'm not exactly sure how I could actually use that.

Have a nice day,
    Henk Boom