Bugeye (02) WRX STI

I recently had a new sub frame put on as old one was damaged. When it came to the road test my machanic noticed that the steering had a knot it it and he cant workout why. He thinks it could be a universal joint or a tight spot in the rack, but he cant understand why its doing this. The Fitment has been checked over by the garage technician and he cant see any problem with it. anyone got any ideas? thanks