Sounds like mis-information to me Jason - there are many of us flying with our 430's hooked up to Experimental EFIS's, and I've never heard of a form that needs to be filled out. There are numerous opinions and OWT's out there, many of them incorrect and held by avionics shops who don't understand experimentals) - but you can go to the EAA web site somewhere and read all about IFR equipment in homebuilts.
Paul