Wow, that roll restrictor is a dead simple design, I might have to have a go at making one . . .
I moved here from a 99 Cougar, so a 4 banger is new to me and I have had zero time to get in there and see how things are put together. How are the motors held up in these cars? In the Cougar you had a mount on the passenger side of the motor and a mount on the trans on the driver side. The mounts basically let the motor hang in the engine bay. Then you had a roll restrictor in the front and rear to keep the motor from rotating/keep vibrations down. People usually filled the restrictors with poly to do what you're doing here.
2012 Focus SE Hatch 5spd sport package, Tuxedo Black Metallic
Road Magnet springs, custom CAI in the works, and fuzzy dice on the mirror