Here is the scoop of the day!
First....you cannot get more flow than the smallest restriction in the system regardless of how freakin large a pipe you put after that restriction or how many pipes you put after it....technically...you reduce flow with more pipes!
Second, as exhuast gasses cool, they slow down and a smaller pipe actually is the answer to maintain flow velocity...(IN THEORY)
Third, two 4" pipes from a single down pipe do not make a dual exhaust...you would need twin turbos one for each side, with their own down pipes and then into their won 4" system. That makes a dual exhaust!
IMHO, save your coin...install a good single exhaust, less to have fail as well! Less expense to replace etc...less to maintain.
Ya I can be a smart ass...so send me the money you save cause I had the balls to say so!
Good luck with what ever you choose, we support ya either way, we just want to see your truck running top notch for the least $ invested..theres better places to invest than another 4" pipe....NEW Injectors....Case of Beer? Lots of places to put that coin....
Send cheque to...
naw...just kiddin!
Al