Leaking fuel tank?
 

Hello, this is my first post here, so I'm sorry if there is already a similar thread, I didn't find one.

I recently bought an '04 RX-8, rebuilt motor (around 10,000 km ago), with 120,000 km on the odometer. When I first filled it up completely, I noticed a strong fuel smell inside and outside of the car. I didn't worry too much about it, since it went away after only a few minutes of driving with open windows. Then, the smell disappeared again, as i never filled it up all the way, usually just to half a tank. Yesterday I refueled it all the way, and as I approached the car today in the morning, it smelled very strong of fuel, and I saw a small puddle of gasoline underneath the car. This time the smell didn't disappear when I was driving it. I then went to a store (10 min drive) and as I walked out again around 15 min later, I found a huge puddle of gasoline under the car, so i crawled down and saw fuel just drizzling from the right outer side of the tank somewhere from the top. That stopped around 15 min later (when the fuel gauge showed a bit below 3/4 of a tank), and I drove home and had no fuel leakage / bad smell whatsoever.
The recall for the fuel lines was done sometime prior to my purchase.

Is it safe to drive the car?
Do I need to replace the tank or could it be something else?
What would such a repair cost?

Thank you in advance for your answers.

Possibly something got F'd up when they did the recall.
Remove the rear seat and see if you can see where it is leaking
Check the retainer ring for cracks or looseness. They might have pinched the o-ring
Also check the fuel pump outlet....it tends to crack at the 90 degree bend at the top of the pump module

Okay, so i checked the drivers side where the fuel pump lives and everything was dry there. No visible cracks in the retainer ring or the outlet, so i removed the passenger side rear seat as well, since the fuel was dripping from this side. When i lifted the metal plate i saw that the tank was wet with fuel next to that white cap. (Picture below)

https://cimg4.ibsrv.net/gimg/www.rx8...9b569390b0.jpg

Why does this side also have this white cap? Since the fuel level sensor is on the other side why is there a plug with two wires going into it?
Is it possible that the fuel leaks from a leaking gasket for that white ring nut?
If yes, can I change it myself and how do I get it off?

Thank you for helping!