Are there any advantages to true duals. I have a 1993 FLHS and I found someone that makes a kit ( a plug for the crossover pipe) to convert the stock exhaust to duals. He supplies plugs for 100% blockage and one with a 1/2 hole for 90% blockage. Would this help or hurt my bike? Does it matter that the pipes won't be the same length? I know on cars with headers, all the pipes are the same length. Does this matter on a bike's exhaust?