[turnsignalslol]

I saw a post on the forums the other day where someone did dyno pulls before and after they installed downpipes on an S58 and it ended up losing power…

Is this something that actually happens without a tune? I know that you usually gain a couple horsepower when installing downpipes on stock tune for older cars like the F and E generation but I’m wondering if it’s no longer true for the G chassis.