So I was repainting my valve cover and noticed that (1) my coil pack were drenched in oil and (2) one of them was missing the rubber insulation tip. I got new seals and cleaned them up. Car runs "okay", no codes or anything but idle could be smoother and such. Do you guys think it's worth replacing the coil pack? Try to get it from a dead one? Leave it as is?

 

definitely fix or replace that coil, the rubber boot mates up with the ribs on the sparkplug to reduce the chance of arcing along the body of the plug. If you see thin pencil lines on the plug body then it has been arcing which will reduce performance.

 

I agree. However, a tech at Honda of Poway CA told me that there's no way to get just the rubber and that if there are no misfires I can just keep it as is instead of spending $100+ for a piece of rubber. Thoughts on buying the cheapest "compatible" one on eBay and taking the rubber piece?

 

You should be able to get a new OEM (Denso) coilpack for around $50 if you do some searching.
Here is a thread with some hints on where to buy https://www.s2ki.com/forums/s2000-un...-packs-845574/

 

glue a bit of rubber water pipe on there

 

yeah new Denso units made in Japan can be had for $45 each on Amazon or other on line suppliers, I bought four of them a year ago at a fraction of the cost of dealer parts, and they are the exact same part as the Honda branded units. My guess is you are losing performance and you don't always feel every misfire.

 

I'm taking my car into Infinite Motion for a variety of things, including this. They're going to replace the rubber thingy (apparently they have a stock pile, good idea on their part) and run compression testing and then decide if replacing coil packs are needed or not. If it is I'll ship them some Densos, unless they have them in stock for $45. $45 vs $200 from the dealer is a huge difference.

 

Don't mix and match AP2 and AP1 coil packs or you'll be replacing all of them.

 

Noted. For now the plan is to not replace any, unless my compression tests show otherwise

 

You should also replace the spark plug tube seals. They likely went bad and allowed oil to get in there in the first place. This could also be contributing to your rough idle (misfire).