I didn't install my setup, but it's not going to be a plug and play installation. Looks like you'll at least have to modify the bottom tray, if not add some plate to it to strengthen it. If you do a google search there are a few links to different installations. 
Mounting Wilwood pedals in Classic Mini

Hi, has anyone got some photos of their installation of the Wilwood (underslung mounted) racing pedals sold on minimania as MT322000. They have the master cylinders inside the cabin and look as though the top plate fwd end would  bolt to the now vacant original master cylinder holes in the engine bay. Haven't been able to install and even holding them up close, I see there would be another issue with hardly any clutch pedal travel possible before hitting the bulkhead. Wilwood have not replied to my email. Looking at their website I don't even see a top plate on any of their pedal setups so I am extra confused. Please send to [email protected] thanks