pcmforlees is a tune-definately a great modand should be next, chips are junk. Exhaust-not much hp but depending on the system you get the sound. Supermodulation has a few upgrades like the supersparkz that replace the coil boots, not much hp but definately smooths out idle. Ported throttlebody from him also is a good mod-better throttle response and if you look closely if you clean yours you will see where GM left room for improvement. Next would be to port your head especially on the exhaust side especiaaly with the pre '06 heads-again GM left alot on the table. From there you would have to do a custom turbo setup as there is no "kit" out of the box to do. Talk to limequat or efi-diy as they currently have turbo setups. Good luck.