i just had this idea when i made a driver pissed off today :) and i was actually giggling while doing that - well, actually it was not done on purpose. he was just being reckless. anyways... here are my observation.. not generalizing but most of them are like this :)
proton & perodua owners: they tend to over modify their cars just to make them feel.. 'uuuhh... i have a performance car - and they are fast!' duhh.... and they will 'cucuk' you on the highway as though they are driving a Ferrari on F1 race.. normally they are owners of wira, waja and kancil... old putra... used to be.. gti.. but they are no longer around so much after neo is out.. perdana owners are another perasan crowd who thinks they are the gangsters... but lately their behaviour has been reduced.
honda owners: they are in their own group. also likes to show off, especially the old honda owners.. i.e. 90s models.. some newer civic owners too. just had one this morning... :)
i will not write on the usual ie giving signals and all coz they are too common. :P