To get one to go 100mph is easy, cost maybe 5 grand done right. To have one cruise at 100 with any degree of safety and stability is at least 30 grand. Not only does the entire suspension and brakes have to go but little things like Z series tires, bear claw door latches, keeping the air from under the truck, air gate or highly louvered tailgate, 3 point seat belts, 4 point cage--more for chassis stiffening than roll over protection, lower stance with at least a 4 degree rake, and a top chop with the windshield leaned back will all help. With the above done and an engine like a 500 Cadillac with huge torque along with gearing in the 250-280 to 1 range will make one cruise on the century mark with ease. This particular truck I've just described will get 8 to 9 mpg if in perfect tune. My whole life I have worshipped speed and have built numerous very fast rides but unless you now live in some place like Nevada or west Texas, where can you hit the century mark except in short bursts? Certainly not on highways that are increasingly crowded with 4dr sedans full of families. I have customers with a GT-40 Ford, a Viper with the Venom Mod, and a turbo'd Z06 Vette that will all flirt with or exceed the 200 mph mark but it is for bragging rights and not something that can be used.