The black wheel arch trimas are available from eurocar arts for £8 each, the sills on that car are BMW M-Tech ones - probably modified o fit the length of the sill ? ECP do loads of suspension kits too, or look at somewhere like venom motorsport (google will find their website!)
There is a thread about smoothing and painting bumpers in this section - although it might be easier to find soem used GTI bumpers with the black plastic top, and painted lower half.
Smoked rear lights - any of the above places, but used VR6 ones normally sell for under £20 on ebay.
Good luck - i'm trying hard to resist doing similar to my reecent tdi purchase, but as mines a 5dr its less likely to happen which can onyl be good for my wallet as it was bought as a cheap runaround to keep the other motor for high days and holidays
