APY injector seals

[pj123]

I've noticed I have leaks around my injectors and want to get some new seals.

Where is the best place to buy these apart from Audi and are they the same top and bottom on an APY injector?

 

[pj123]

Would 8 of these be correct?
BS203 3.53mm Section 7.52mm Bore NITRILE Rubber O-Rings Simply Bearings Ltd