I believe the answer to your question is different depending on which version of mod_security you're using. I'm not familiar with version 1.x but am with 2.5.x.
In 2.5.x I examine my audit log and when I find page requests being blocked I add an exclusion for that specific page and that specific rule rather than a global exclusion. Multiple rules can be excluded in the same block by separating with a comma.
I created a file named modsecurity_crs_60_custom.conf in my mod_security conf directory and then added lines such as:
#Rule to exclude such and such.
Hope that helps!