When I took my stock spoiler, I used go gone and it worked for me. Here's some before and after pics.
MPT TUNE, Borla S-Type, Airaid Cai, Ford racing X pipe, Mac ceramic shorty headers, 2010 GT500 rims, 35% tint, Sr Springs, J&M phb, camber bolts, blacked out side markers, front and taillights.
2016 GT RACE RED MANUAL aka " RAGING BULL"
Borla stypes cat back exhaust, tint kit all lights, 5.0 race red shift knob, MMD V SERIES SPOILER... and more to come...