3” vs 2.5 “ tailpipes question

[Vegas69]

You'll never know.

[SSLance]

My 3" header collectors adapt down to 2.5" and run all the way back through tailpipes out the back with 467 HP, 525 ft lbs at the crank. Packaging on street cars is tough and I'd rather have a tame exhaust that fits than forcing a 3" setup in where not really needed.

[NOPANTS68]

You spend 99% of your driving time under 4500 rpm so the flow isn't an issue. Plus, you're not dragging extra weight around from the larger pipe. 2.5 mandrel is good for an NA LSX all day long. I had 2.5 to the bumper on my LS1 Nova and still trapped 118 mph with just a cam.

[Ripped]

I think some of it depends on engine cubic inches. I switched recently from 2.5" to 3". The diameter change in the pipes is massive. Fitment is tough. I cannot tell you what a combo system will look like 3 and 2.5.

There's an engine masters episode on 3" exhaust here; https://youtu.be/_PVXvHkr-Vs

When I made the change, the exhaust note went from loud to deafeningly loud with the 3". I freed up a lot of power, and went from scary fast to dangerously fast and you better respect the power or else fast.

What cubic inch is your 500 coming from?