You get what you pay for...I would NOT trust one of those ebay setups unless you replace the turbo with something better and I can't imagine the manifold will fit a Cobalt. It may, but I don't know for sure.
I would recommend getting a list of what comes with the kit from Garrett or Hahn or one of those well known companies, then finding all the parts online separately. You'll spend more than twice the price of this, but you'll have something you don't have to worry about.
Man just from looking at the parts. THat is a very cheaply made product. With the money they are asking you are better off to buy a garrett. If you are going to upgrade to a turbo you might as well spend the money to do it right instead of spending money to constantly fix mistakes and problems that arise from that kit. Plus you have to look at Tunning it and everything.
The Garrett® Chevrolet Cobalt Turbo Kit is for the 2.2L Ecotec engine for LS coupe and sedan model years 2005 and above. A GT2860RS "Disco Potato" ball-bearing turbocharger and all of the necessary components are included to complete the installation in your own garage!
Chevy Cobalt LS and LT coupe and sedan models with the 2.2L Ecotec engine
Model years 2005 and later
Garrett exclusive ball-bearing turbo for unbeatable response, efficiency and durability.
Four trim levels are available, from a complete solution to a tuner's dream.
Garrett® Turbo Essentials Kit (P/N 772764-3)
Garrett® GT2860RS Turbocharger
Cast turbo manifold
Cast down pipe
Gaskets and fasteners
Garrett® Turbo Essentials Plus Kit (P/N 766621-3)
Essentials Kit items
Oil and water lines
Garrett® Turbo GT Tuner Kit (P/N 766621-2)
Essentials Plus Kit items
Charge air cooler
Charge air cooler plumbing
Garrett® Turbo Alpha Kit (P/N 766621-1):2005-2006 Manual Transmission Only
GT Tuner Kit items
Engine Control Unit *
Larger-than-Stock Fuel Injectors
Garrett Brand Boost Gauge
* Once the re-flash tool is used on a particular vehicle, the tune is non-transferable. The scan tool is VIN-specific and only works with the first VIN that is entered. The calibration of the tool is locked to ensure the integrity of the calibration. Use of a piggy-back system or changes to the calibration may result in engine damage.
You could even pick up a used kit from someone selling theirs on CSS or someplace else. One of the nice things about the Garrett kit is that it's super easy to install and the instructions are great...I never thought I'd be able to do something like that, but after reading them, I'm positive I would have no problems.
I'm guessing an ebay kit won't have that kind of detail...then, unless you know what you're doing or have a shop do it, you'll wind up wasting more time trying to make sure you get it installed correctly.