Ted is right about the addition of a 2.55 upper - the IAT2s skyrocket and the amount of timing you need to pull makes the gains negligible unless you are driving on race gas. I have attempted multiple pulley combinations and found this to be true. I am working with D3PE to try to construct a revised intercooler - but as of yet it has not happened. If anyone knows of a company building intercoolers (not HX) for a ZL1 let me know.
2012 A6 Coupe 630RWHP
Mods: ID850 Injectors; Custom fab D3PE heat exchanger, reservoir, and atmospheric catch-can; LPE 2.55 Upper and 9.1 Lower S/C Pulleys w/ Damper; Cat delete;ADM Exhaust Valve Override; Magnaflow X-Pipe Muffler (in addition to stock mufflers); 160 degree thermostat; Solid (LS9) Isolator Coupling; Port/polish supercharger snout and intake runners; LPE GT9 camshaft with dual springs and titanium retainers; Kenne Bell BAP, Install and Dyno tune by Serious Hp; Fab work by D3 Performance Engineering; Coming Soon: Trans Tune and Flex Fuel Conversion.