definitely pull the taillights, (it's only 3-4 bolts) and run a bead of silicone acros the tops.
if you want to be certain of where it is leaking, open the trunk and pour water in the channel starting at the middle by the glass, make sure to have some towels handy to catch spills and leaks. the water will run down the channel and show where the leaks are.
R.I.P fast 6
Two wheels or Four, I'm happy as long as the throttle is pinned.