Well Bryan's link didn't pan out but I have great news anyway. I found a boot and bumpstop that fits like it was made for this combination:
KYB SB108
KYB SB104 will also probably work. Supposedly its bumpstop is a little shorter. I bought the SB108's to be on the safe side.
The boots are very narrow and fit perfectly inside the tiny GC springs. The bumpstops are separate and lock into the boots via a lip system.
The bumpstop can be pushed over the Koni's flared mount stop, but it grips very tightly. An added bonus is that the boot isn't floppy but rather pretty stiff and it can support itself and the bumpstop without any problems. So even if the bumpstop tried to slip down the Koni's flared stop section, the boot would hold it up. The bottom of the boot fits the shock body perfectly. So perfectly that it slides around the shock body and is still skinny enough to fit inside the threaded sleeve!
My only concern right now is that the bumpstop may be a little long and would benefit from trimming. The shock arm normally stops when being compressed at the flare section. The bumpstop holds on to the flair and extends down and past the flair ~ 1" That sounds like a pretty decent length to me, but I don't know how much travel I'm going to have when I get the car at a ride height I like. Any thoughts?
Lane
PS
Oh yes. I verified something else today. The GC coilover kit comes with two different pairs of threaded sleeves. There is absolutely no instructions for which sleeve pair goes on the front shocks and which sleeve goes on the rear shocks. So.... of course I did it wrong. The result was a very low front end even when I'd maxed out the adjustability of the threaded collar and a high rear end. I've driven the car like that (only ~ 1.5 miles total) since I put them on almost a year ago, but I've always suspected that was the problem. Well today I found my suspicions were correct.
If your collars look like this on your
front shocks, you're doing it wrong and are doomed to do what I had to do and take out your whole suspension and swap collars with the rear.
The right way for it to look is that you should not be able to see the yellow of the shock poking above the collar.