What would give me more horsepower, new intake or new exhaust?
Depending on the engine size, cold air intakes usually give you an increase of about 5-15 horsepower. Exhausts systems typically claim to get in the 10-25 horsepower range so I think you'd be better off getting the exhaust done first. But doing both would actually be best because the new exhaust would be living up to its potential, if more air was coming through the intake. And the intake would work best, if it had a less restrictive after market exhaust. So why not do both? A cold air intake would be cheaper though, around half what a whole exhaust kit costs