I thought it worthwhile adding a few links to some parts and spares providers that are specifically useful to Italian replica builders/owners, as I've spent years finding some of these and i thought it may save others a bit of time.
Please feel free to add any i may have missed:
http://www.eurospares.co.uk/Index.asp - - OEM Ferrari / Lamborghini / Maserati parts
http://www.lambostuff.com/ - - Lamborghini specific parts, manuals, stuff....
http://www.dcsupercars.com/ - - DC Supercars - Countach / Diablo replicas & parts
http://www.superformance.co.uk/ - - Ferrari parts specialists - some parts crossover with some of the old Lambo's as well.
http://www.rimmerbros.co.uk/ - - For all your Rover V8 goodness.
http://www.cbsonline.co.uk/ - - Car builder solutions - for everything generic kit car related - also a good source of alternative Lamborghini dash vents!
www.ak-tuning.com/ - - A good source for 'Raid' type steering wheels.