If you want that much more power out of a Vulcan, you're going to need Nitrous and or a turbo. And then with the stock engine internals, don't expect it to last long. If you want more than 1 horsepower per cubic inch, you need to seriously beef up the insides of the motor as well. Forged crank and rods, hyper or forged pistons. Lots of head porting and a bigger cam, High flowing intake and exhaust. Get ready to drop a LOT of money into it if you want it to be reliable. Better idea is to get a Duratec or SHO car.
To get the most out of a Vulcan without sacrificing reliability, just maintain it real well, put on a set of spiral core wires and double-plat plugs, keep the air filter and injectors clean, and maybe, maybe, a custom freer flowing exhaust. A muffler shop can probably install something from the cats back that uses 2-1/4 or 2-1/2 inch pipe. discard the resonator and replace the stock muffler with a Magnaflow. I do think the stock 2" exhaust on Taurus is somewhat restrictive. No worries about leaning out the engine, the lean condition from reduced backpressure will be detected by the O2 sensors and then the ECU will command a higher duty cycle on the injectors to bring the ratio back into spec.
