benneh said:Bit late in the day but a Rover Ti airbox looks about right.
Here's my old one off the car
I've seen them in >250 BHP cars with various panel filters inside (seem to do a fine job). Not too big either, but plenty of flow.
That looks ideal, what model rover and years is that fitted to? Might try and source one to see how it fits to try and keep an OEM look under the bonnet.