you can check the www.yokomousa.com
site for a side by side comparison. but basicaly the ssg and black are same car the ssg is silver and the black is....well black. they are both top and bottom plate style cars with a shaft. the cgm is a tub style chassis with shaft other then the steering rack setup parts are interchangable between cars. the cgm is slighty heavier, but stiffer and doesn't tweak. the worlds car is way different then both the ssg and cgm, open drive train, lower cg, etc. as for hop ups, some lighten the car and reduce the rotating mass. some help with setups. check the yokomo sd thread on here for more info on that or post any questions you have there you will get more help. good luck and happy racing.