Nah Piggy, that's a list of already has
So when they crack, and they will, replace with stockers and match port them to suit head and turbos
500 at the wheels will be easy with what you have, 600 will be easier with a 3.5" exhaust
Get rid of the HKS spark amplifier, it will cook your coils at some point, splitfires are ok for 600 but the Mojo LS2 coil kit with built in ignitors would be better, they have a kit that plugs in and deletes the ignitor