sister car similarities

we all know how the cavilier, and sunfire (and some grand ams) are sister cars. well, the zx2 has the cougar. so my question to you all is how closely are these cars related. i know the cougars ran vct 4 bangers (but we didnt get the 6) like ours, and i think the same tranny (in the 2.0). and in all actually i like both cars, but if i were to tune them would they react the same? and are the computers the same?

they arnt sister cars, if they are sisters cars then so is the Puma, and Contour since they have the sema motor, the Cougar has the focus tranny. The computers are the same PHYSICLY, but the tunes are differnt the Cougar/contour has different cam specs.

the courgar/contour are sister cars, they just have motor relations to the zx2.

the cavalier/sunfire are both j-bodies, so they are the SAME PLATFORM, the ZX2 really doesnt have a sister car. well, the Escape is really close