BBK Chrome Longtube Headers..Will I lose power?

They can cause poor drivability (surging at idle and poor gas mileage). This is because they don't hold exhaust heat in very well which causes your O2 sensors to give faulty readings. If you’re going to get long tubes get the ceramic coated ones because not only will they last longer the coating also holds heat in better. Your car may run perfect with the chrome ones, but I've been there and done that with set of HTS coated MAC LTs on a 5.0 and after a year of stalling, surging, and 120 miles out of a tank of gas, never again. Just my 2-cents.