Forgive the ignorance of someone that has only pulled K-Jet injectors... but FCP shows 3 seals per injector - and IPD shows 2... Which business can't count? (How many seals does each injector require?)
IPD (seals for all 4 injectors):
https://www.ipdusa.com/products/5898/111181-fuel-injector-seal-kit
FCP (seals for 1 injector):
https://www.fcpeuro.com/products/audi-jaguar-porsche-volkswagen-volvo-fuel-injector-seal-bosch-1287010704