Originally Posted by BLKSVT
After having a lightning for years now, my thought is use the magnaflow with the built in X, leave it 2 1/2 and call it a day, however you are running true duals. I was making well into the 400hp range and had 540ftlb of torque with that set-up. I deleted the cats, put LT headers on and lost torque, down to 535. Most stock exhaust can handle almost 500hp and high torque ranges from what I have learned. It's a tweaking game at best with your programmer, to pull out the powa!
totally true...an exhaust system in itself almost requires constant upgrading especially as anyone mods up. it took alot of tweaking before i was totally satisfied with my setup..