you can get a FUELCELL at most performance shops , but it wont be a strap in and fill deal
you will need fuel pump and surge tank, also the lines and mounting straps plus loosing all the trunk space
s14 gas tanks can be plastic welded, i had one with a crack took it down and welded the crack never had a problem with it again
also its a pain in the ass to take down, you need to drop the whole rear subframe, disconect the fuel lines and then deal with the clips that hold it there
i did it in my garage but it would be WAAAAAAAYYYYYY easier to do with a lift
carisma llc here in orlando has 2 very clean tanks, i think they are 150 each and i am sure down in miami you can find someone to do the work if needed