You wont loose power, but you will loose performance, just simply from the extra weight of the doubled-up piping

I find it funny that exhaust fitters, which requires no experience in anything, are suddenly experts on fluid dynamics and gas velocity after starting the job

I think you will find that a quality system, of smaller diameter, will generally flow better, and give more power, than a s**t backyard large diameter twin system.

I think you'll find about 2hp difference between the best and worst quality off the shelf systems. (given like muffler design) the noise would differ a bit more.
As ALL of them are just a 2.5inch bit of pipe bent to fit under a falcon with a muffler or two jammed in there.

How many people here have any practical experience with exhaust systems?
(and i'm not talking about buying a premade system and bolting it one. I also don't mean who has worked in an exhaust shop)
I'm talking about actually sitting down designing and building the system and then proving the results through what ever means.

I was going to reply to this thread, but then I couldn't be f**k, looks like the pro's are all over it.