I know you are referring to an Escort,
but i put in an SR20 into my Mk1 Cortina myself, quite simple IMO, as it came out of my KE30 Corolla so had a good idea on how to go about it, and the Cortina is engineered full cage and all,
I did look at a 13B Turbo, but the engineer says that it would de-value the car, cool for noise, power numbers and space, but take it to a show, ill prolly get slapped,
If you have had a Rotory previously, just use a rotory crossmember and mod it to bolt between the chassis rails, and use a 12A timing cover,
I admit Ford engines in small fords are cool, and compliment the car, i only chose the SR20 cause of the availability of parts, tuning, and ease of power, and the exhaust on the passenger side helps in terms of master cylinders, im looking at this atm, and steering towards nissan or wilwood units to pump four wheel discs, and compact unit as sits close to the clutch master, if it works out the SR manifold should sit above these out of sight (be nice)
Seems there is alot of support also for Ford motors via this forum, and many people willing to give good advice