I just bought spark plugs for my 40K service.
These were 55p cheaper each than OEM.
http://www.spark-plugs.co.uk/
Results and Information
Make
SEAT
Model
LEON (-->08/05)
Production Year
03/00-->
Engine Size
1.8
Variant
20 V TURBO Incl.CUPRA
Engine Type
AJQ,AMK,APG,APP,ARY,AUQ, BAM
Additional Info
Not Applicable
Standard Gap (mm)
0.8
If these details do not precisely match your vehicle please begin again
Iridium IX Part
Part Number
Price (£) Per Plug
Qty Per Set
BKR6EIX
5.89+vat
You can use any decent 5w-30w Oil, Millers, Fuchs, Mobil or Castrol Edge.
Filter I'm not too sure, just a generic OEM from a stealer I think.