There's no harmful effects really from straight pipe. Long as you keep the exhaust flowing well. Throw dual 3" pipes on, yeah your truck will have the power of Prius. Choke it down to a single 2" pipe, your truck will have diesel like tq until 1000rpm then it'll run like junk. Small pipe increases tq because of scavenging and pulse velocity and large pipe increases overall hp because of flow capacity. Balance the 2 and you'll increase performance throughout the range. Little more velocity and tq will net better mileage at cruise

 

So we need a variable back pressure exhaust? Lol

 

You completely misunderstood that unless you're being sarcastic, hard to tell online.

The point I'm trying to make is you have to balance pulse VELOCITY with flow CAPACITY. Choosing the right size pipe, muffler/s, headers, and cats/or none will give you good low-mid tq without choking your top end and killing hp

 

I was kinda joking but kinda not, imaging an exhaust that's relatively closed to increase back pressure at lower rpms and open up to the full pipe size at higher RPM.

Seeing how stock is a 2.5 pipe I'll stay at that and 2.5 to a bigger tip on the end when I do mine

 

2.5 is about perfect for single exit on anything less than stroker or boost actually. That's why I'm sticking with it myself

 

Now I want to mess around with tones I want a deep tone so I'm gonna run the 2.5 from the end and farther towards the end I want to run a diesel tip size for my own reasons I wonder if that would act as a megaphone or deepen the tone

 

It does megaphone it. I currently have headers stock cat and no muffler with 4" tip and it echoes a lot compared to the 2.5" pipe it's on. In about a week I'll have a carven R series split with a y adapter into dual 45s with 4" tips

 

I really want mine out both sides in front if the rear tires but the gas tank is kinda in the way