Besides fitment, which I can't speak too, there shouldn't be any mechanical issues with running the newer can on your 04. And pretty much any aftermarket option is going to be louder than stock, and most should be smaller at least by a little.
That statement is so extreme it's false.Are people still talking about backpressure? Ideally you want zero backpressure and it's scavenging you want so it pulls the exhaust out of the cylinder.
It's all about balancing your torque and hp, and this of course depends on the type of riding you're doing.Small diameter increases scavenging and gives you low end torque but creates back pressure in higher RPMs. Larger diameter loses scavenging however lets your exhaust flow better at highwer RPMs giving you more power up top.
The term is VACUUMYou want negative pressure
Exhaust velocity is what you're going for.Think of a can of cream of mushroom soup and when you turn it upside down and the suction that stops it from coming out. Now if that was a longer tube and you had 2 gelatinous blobs of cream of mushroom (yeah, I have weird analogies lol) and both ends of the tubes were open. If that first blob moves, it pulls the second along with it from the suction (negative pressure) and that's the same with exhaust pulses. If you have a narrower tube then it pulls more effectively where as a larger diameter the pressure is so dispersed it isn't as effective. Removing the header is just having the exhaust "fall out" as opposed to being pulled out.
Yes, and scavenging is what does it at lower RPMs.Exhaust velocity is what you're going for.
Cause and effect is fun.Yes, and scavenging is what does it at lower RPMs.
Steel understands too well and can confuse himself by over-thinking absolutely everythingSo this is what it's like talking to someone with a deep understanding of motors...I like it lol