The sierra drive train is similar to the escort anyway, the problem is the extended arches on the escort cossy.
The wheels might fit but they would 95% chance of hitting the callipers front and rear and the legs.
As Jakub says you need to come out to at least ET20, which is the equivelent of using a 15mm spacer kit.
I sell the proper ones and have 30mm ones on my car for 2 years.
We get them to TUV spec and are 100% safe to use on and off road.
If you want or do get the wheels contact me for the spacer kit