Somewhere around 280 - 310 horsepower I would estimate..

I am not drag racing it, but have driven the car somewhat hard and had no issues. Car weight is less then some US cars that might help too, at abit under 3k pounds.

The 4 cyl 'Stangs use a different length input shaft from memory, different ratios then a 5.0 and not sure if they are even WC boxes?
The SVO cars "may" be an exception but I don't really know for sure.