What parts do I need for injector seals

[Roa, Greg]

Hello all,
Just had a quick question.
Say I wanted to replace the fuel injector seals for my 4kq.  What parts should I get?
Is it just the seals, or are there other parts to it?
On the parts connection's site, it lists upper and lower seals, upper and lower seat seals, seat retainers, and seat inserts.  I don't know what of this I ought to be getting new of.
If I get new injectors, I suppose none of these things come with them, or do they?

Thanks!
Greg Roa
Cincinnati, OH
86' 4kcsq
93' 90 CS
83' 944