Just one thing to keep in mind is that fuel cells have life limits. So stock tank would not have the repetitive cost of renwing the bladder. You might want to check up on the cost of the ballder alone for the ATL cell you are considering. Having said that......Personally, I would rather have the cell inside the car than the stock tank inside the car as with your Datsun. The reference I made to OEM tanks performing well is for outside mounted tanks; inside is a lot more problematic. I have seen one that came loose from its stock fasteners in a rollover and gas went everywhere. It was a scary moment for the occupant......
I find it interesting that FIA is now charging a fee for the hologram thingy ( see here:
http://www.atlinc.com/new-FIA-labeling-and-hologram-requirements.html )....a new revenue stream at the racer's expense.....but the mitigating part is that it is required in FIA sanctioned events. I have to wonder if the same is going on with the $50 fee from Jaz to add SFI certification to their cells. The cell will work the same with or without the label. I know I would pass any cell that has the mfr's FT3 labeling other than the hologram label.
Mark B.