As you indicated, there are pros and cons to having a fuel cell.
Given your previous post, I gather that you are thinking about competing the car. So, a fuel cell is a good idea.
- Less likely to suffer from fuel starvation while cornering
- More accurate fuel readings to determine mileage.
- Fuel remains more stable for a longer period of time and is less prone to evaporation
- Fuel is centrally located and sloshing doesn't occur as much to affect weight transfer as fuel shifts inside a conventional tank (It can't do that with a cell)
- Usually requires a high volume fuel pump to work effectively. The stock pump will NOT work
- Less fuel capacity
- To install, you need to make modifications to the rear trunk - It will not fit at the stock mounting points
- Fuel vapor can enter the car because of the installation needed
- You cannot pull up to the pump and use a conventional nozzle to fuel. Fuel cells are "sealed" systems that require a special filler nozzle to allow for fueling.
Bottom line is that a fuel cell is neither a good or bad idea. It depends on your application. If you intend to race the car, then definitely a good investment. If not, then save your money. The expense of the cell, fuel pump, special filling equipment and the installation can easily reach $1000 or more.
Pro/Con....sometimes the sanctioning bodies rules (SCCA, NASA, etc) require them. Pro...in a violent crash the fuel tends to be localize (largely confined to the bladder) and doesn't splash all over the place. Pro....you can locate the cell for better weight distribution and balancing.