Eric,
I would suggest you e-mail the contest director at IPMS First Coast (hosts) for a correct ruling. Their web site and links to JAXCON are both available through the IPMS/USA website.
In general, the answer would be, no. Regardless of the reasons, adding any scratch-built or additional components beyond what's provided in the kit will push the entry out of eligibility for OOTB. There are a few execptions in the IPMS rules (simple tape seatbelts, various antennae, etc.), but I think yours may be outside this guidance. Since every contest is allowed to have their own rules and even modifications to the IPMS National rules, the host club is really the best source to answer your question.
Hope this helps...