I don’t know about S2K tails, but many cars taillights (especially those on imports) can be opened (and thus cleaned and resealed) by first:
Removing from the car
Removing any electronic components (bulbs)
Placing in oven (to soften glue component), (On towel, on cookie sheet)
Removing from oven and slowly prying lens from housing.
Once removed, scrape and clean old Glue.
Replace with new Hi-temp Silicon adhesive
You might search forums for people who do this on their Heads to get an idea of what temp and specific glue needed.
Check this out as well:
http://www.s2000.com/forums/exterior...er-lights.html