The shorties are perfect for the guys that are not wanting to deal with Tuning and CEL's. Straight up. Of course they aren't going to make 25 rwhp like some of the LT's out there.
They will make 8-15 all day long however. We do it everyday here at Southwest Speed and there have been a few C5.com customers who have even posted up their own dynos to show those gains.
Short tubes will never ever make power like full out race headers will. But that was never the designs intention and for what they are designed to do, they do just that.
Keep it fresh and enjoy your Camaros!
Ivan