you should not ground on the rear deck cause its could be a flotting ground, under the mat should be perfect and the best, if you want to work hard, the back seatbelt bolt
1998.5 Toreador Red/Midnight Blue Contour SVT - #5912/6535 - DOB - 05/11/1998 -
RU-3530/CTA Intake Pipe
MSDS Heaser/Y-Pipe
Magnaflow #10435
9mm Ford racing
SPEC Stage one/Spec Alum. Flywheel
HERE