They now have this stuff in a spray can that makes things ice cold which would cause the bolt to shrink and shouldnt hurt the paint. Saw it on the weekend truck building shows on Spike. Also may be alot safer than a torch near the gas tank.
Ez-out...........last resort. With the t40 fitting in the bolt head it should be pretty easy to hit the center of the bolt. If you are using heat I wouldn't use anything but a hair dryer. Anything else may peal the paint or............worse.
Sometimes when drilling the bolt head to use an Ez-out the (if you get in the center of the screw diameter) screw body will collapse and loosen up.
Impact driver if you have access. The spray stuff sounds cool, soldering iron if you go heat. Personally I would drill the head off of it before trying an easy out. When you snap the easy out off, there will be no drilling after that unless you have some dental burs and some skills.
It doesn't seem like applying heat would be the solution. That would cause the bolt to expand. You would need to heat the frame where the bolt is inserted I would think. Cooling the bolt would cause it to contract, such as using the loctite spray that has been mentioned.