[GT40Racer]

Good old Oxford dictionary says
"a person who collects things of a specified type, professionally or as a hobby: an art collector."

Some other online definitions:
A person who collects objects is called a "collector" or a "hobbyist." He may also be called a "compiler" or an "accumulator." 

Perhaps those that don't race them are accumulators or compilers :)

The hobby of collecting includes seeking, locating, acquiring, organizing, cataloging, displaying, storing, and maintaining items that are of interest to an individual collector

Good discussion - I have no issue with telling people or someone saying I collect slot cars. However I don't collect chairs. :)