If a strut is leaking it must be replaced. I would replace it all. If you don't get a quick strut then I would replace the strut and everything except the spring. If you have a lot of miles I would also replace the spring.
Inserts were old time. Don’t think anybody does any more.
I’d use complete assemblies, so much easier. Monroe makes it for both w/ and w/o sports suspension. And they cover normal wear as well. So no need to pay for another set except warranty shipping (details on rockauto). Watch for their buy 4 get cash card back deal.
KYB doesn’t cover normal wear, but some members like the firmer ride. I think it’s too harsh in its inability to properly handle road cracks and lane tiles but YMMV. IMO KYB = Keep Your Bilsteins.
Thank you all! Back in the day we could replace just the inserts.? Was hoping there was an option to save some money. I will definitely watch for the sales, thanks for that reminder! I always use factory parts but in this instance I may stray from the norm. Thanks again!?