Take it you have never had a superbike.......
Spares are very expensive......like things that go on yachts. Seems it sends the price skywards.
aaah!
Halfords do a range of bike service bits, I use their fully synthetic bike oil, about £30 for 5L, filters are around the £5 mark... Not bought plugs for the R1 yet, but I did my old Blade plugs for £25.
Try this site
http://www.patternparts.net
they dont list zx12r for spark plugs but the zx9r gives the same NGK partno as the ebay ad.
Makes it about £40 for plugs and oil filter
I always found that like for like, i.e. main dealer v main dealer or DIY v DIY, a super bike was more expensive to run than a tin top.
Paul G