when i did one we used tape on all of the flat spots so middle grill and fog light holes and a few bolts in the fender wells to hold everything together.
Instead of double sided tape use urethane. Same stuff they use for windshields. Go into any local windshield shop and ask to buy a tube. Will load into a regular silicone gun.
I'm confused too. I recall a couple years ago a few people using early 90's Accord lips (93-95 or so) on P5 bumpers and it kinda looked like a mini DG lip.