headers are the one thing ill buy from ebay fro these cars, ive had two set of the DNA motortuning headers for $200 and NO fittment issues. you can even find the speedy daddy headers there too
Stainless SS Racing Manifold Header Exhaust Grand Prix GTP Regal Impala 3 8L V6 | eBay
either way you want the SLP knockoffs for the best fittment