Re: new found straight pipe performance (long)
Straight pipe, cat only, cherry bombs, glass packs, even "look like glass packs" - too expensive!
When you get caught on Federal land (Forestry, BLM etc,) or some state's lands, you'll find out how much it costs to have the Ranger call a tow service - or helicopter to remove and impound your vehicle. Fines, removal fees, and even the lawyer to keep you out of jail can be very expensive.
Reason - the engine may put out hot sparks or hot chunks of carbon - especially from the CAT. A baffled muffler behind the CAT is the only legal exhaust on those lands.
There are small turbo type mufflers that are OK and don't restrict much. There are some aftermarket mufflers that look like a straight through glass pack, but actually have baffles. But to prove it has baffles, the Ranger has to poke a stick up to feel them - they won't bother.
That's not just bull, I live in one of the most popular rock crawling areas - Johnson Valley CA, home of the Hammer trails - and see vehicles cited and towed frequently for that.
I wasn't cited, but was told by a ranger about my Jeep's new glasspacks. Furtunately I wasn't off road at the time - I was in a coffee shop parking lot!
The old wives tale that you need backpressure is bull!
Can you run constipated?
Why would anyone ever think that leaving old exhaust gasses in the chamber helps it run? If so, why not just pipe the exhaust back into the intake? That's what EGR does - notive how it inhibits performance!
Most any exhaust will tend to scavenge the old gasses to an extent. You want it to scavenge, but not inhibit the flow.
If it runs better without part of the exhaust, you did something wrong in the first place.