A different EGR setup was used and a throttle body was fitted which wasn't there on the 45bhp.
Unfortunately, these small additions reduced the amount of space in the engine bay even further.
Space was tight before but in previous diesel model, everything in the way was a soft pipe.
These were easy to remove and get out of the way so the airbox lid could come out.
On the 54bhp model, you had the intercooler and the throttle body in the way, neither were moving.
So, how do you get the air box lid out of the way to change the air filter?
This is the method I discovered when smart redesigned the air intake pipe on the non turbo 451.
Previously it was fairly easy but they redesigned the pipe and the resonator boxes making it hard.
Dave E contacted me asking how it was done. I supplied the knowledge, he supplied the photos in return.