hi mate, both the chassis are more or less the same, there are a few bits ands bots that are different. the gxe10, is basically your is200 chassis, the sxe10 is the altezza chassis, however it is just about the same..
i bought a set of coilies a few weeks ago and had them fitted to my is which is a gxe10 chassis, however the coilies were advertised as sxe10, so i am confident in saying the coilies that you seen that specify the chassis, will fit your care.
i went around in circles about the same issue a few weeks ago.