For hundreds of dollars you can get 5-20 hp gain max ~ headers, light weight flywheel, CAI,...etc. For thousands of dollars you can get 50-100+ hp ~ turbo or supercharger, meth injection, tuning...etc. If you can do the work yourself you can save a ton. Increased speed is directly proportional to ones willingness to spend money and/or time.depends on what i can get. what do you have in mind?