Coil Isolator

[jeeperjohn]

That part is designed to go on below the stock isolator from what I can see.

 

[Shorty]

I got it on by grinding the lip and grease. Then a screwdriver and pry it over the rest of the lip.

if you're playing with the '87 in your sig, and you need to pull it apart again, the entire bumper and metal bracket with the rim around it should unscrew as a unit. Grab a big pipe/monkey wrench and "lefty losey" it right off.

 

[magimerlin]

as stated above you could have put a pipe wrench on there and they will come unscrewed very easily.