Guys what is the advantage and disadvantage of these to type of fuel cell. The tail tank with bladder and the 11 gallonn hard plastic tank with fiberglass cover on a mini sprint

The tank/cover deal is cheaper and lighter. Bladder is safer, costs a lot more, gets the weight lower in the chassis. For me the bladder is the way to go just for the safety. I ran a Bailey tank and cover arrangement for several years and had zero problems with it. I did convert that car to a bladder tank because I thought it was safer. JMO

Will be running gas does that make a difference

Yes, huge difference. I posted some stats earlier this year comparing the BTU's and explosiveness of gasoline and methanol. I don't feel like trying to find it, but essentially, gas catches fire much faster, and burns hotter than methanol. I would go with a bladder running these big tracks and on gasoline. You can never pay too much for safety.

People who need performance need diesel. Take a look at those who do serious work-what they have in common is diesel power. For example, the military, trucking, railroad, mining, construction, and aviation industries all use diesel fuel. The United States is the only country in the world dominated by gasoline. In fact, we use more gasoline than the rest of the world-combined!

Don't buy a bladder for methanol and then run gas in it-different bladders required.