iv the same exact thing and i think it needs the short course rear bumper brackets thats the route im looking into for it
https://www.google.co.uk/search?q=hpi+baja+5sc+rear+bumper&safe=active&es_sm=93&biw=1024&bih=667&source=lnms&tbm=isch&sa=X&ei=TRFTVc7xGabV7gbpwIDoCQ&sqi=2&ved=0CAYQ_AUoAQ#imgdii=NEQH0yUl02zE3M%3A%3BNEQH0yUl02zE3M%3A%3BIJnGmRMug2x3QM%3A&imgrc=NEQH0yUl02zE3M%253A%3BBer-FuY9JwE7wM%3Bhttp%253A%252F%252Fi755.photobucket.com%252Falbums%252Fxx199%252Fteamchase8%252FIMG_3594-1.jpg%3Bhttp%253A%252F%252Fwww.rclargescale.com%252Fforum%252Fhpi-baja-5sc-5t%252F4961-hpi-baja-5sc.html%3B1024%3B768
hope this helps cos thats what i will try when iv the funds