Well
No doubt a full exhaust and headers is only worth 10-20 WHP on
stock ZL1s (Both gens), but it will gain a lot more with a tune + more boost. So let's say you do Intake, Pulley, and tune. You picked up 50 WHP. Now, the headers may add 30-40 RWHP now, so yes, IMO headers are always worth it and always a great base mod to grow with the car. Now if you're not adding boost then yeah the $1200-$1500 may not be as well spent, however it's never going to be a waste. Plus the car will sound a helluva lot better