you would not need the spring compressor, thats only if you are replacing the springs. i would not let the caliper/brake part "hang" much too much risk of ripping the assembly out of the boot then you have $$$$ problems
if you have the choice get the base model cruze over the cobalt. its just a way better built car. gas mileage is better and the looks are better. the cobalt will give you issues
you can check other cobalt forums for those who are selling their superchargers. you should peice your kit together to get the lowest price...
check the stickies in teh car build section
m62 come stock from the factory on the cobalt ss from years 2005 to early 2007. most 2.2s get their superchargers from them. costs upwards to 1200 for a brand new one. where as you get a used one from another cobalt owner for 300ish
dont its a scam. it doesnt do anything. the only supercharger that you should buy for your cobalt is a eaton m62 and it takes an entire kit to swap it onto your base model
my recommendation is to upgrade the shocks and struts to FE5's you will get a better ride and its 100% designed for a cobalt, (came factory on the SS models and they are directly interchangeable)