I have a 2007 ss/sc that I've had for a few months now. I put in a 3" pulley and a CAI. I was on the turbotech racing website when I found a complete turbo system for my car:

Hahn Chevy Cobalt S20G Turbo System 2005-07 2.0L Level 5 - Forced Induction - Turbo Tech Racing, LLC

Besides the huge hole in my wallet, whats the downside to converting??

 

Downsides:

Not OEM (fitment, tuning, resale, ect)
No more S/C Whine!!
Turbo Lag
No Warranty

Upsides:

More Power
Turbo Whistle
More Torque
Lower IAT's
No more failing I/C Pumps!!

 

Piecing a kit together will be less costly 20g is a thing of the past....ZZP is where you wanna go for good turbo kits or partial kits.