is there a skideplate for a 98 zr that goes over the built in one now or only the one that replaces
thanks

Both, check at planetarcticcat.com
They have rear skids too http://www.snowmobileworld-s2.com/forums/iB_html/non-cgi/emoticons/wink.gif

Yes, they have em. *Had on on my 98 ZR600.