I think i posted bout how to convert to 4WD from 2WD and make it legal b4 in other forums, anyway the legal way is to install at a JPJ approved workshop and get written letter by that workshop that your conversion is 100% legal and fully road worthy. How much this will inccur I am not sure. Then u need to send your car to puspakom for inspection with the 4WD system and make sure they test it properly. With all the legal letters and inspection JPJ dont have reason to sita your car but durin the period it's not approved you might encounter problem unless u have the letter of pending for approval.
Do check jpj website, 2WD to 4WD is under special modifications, which pengarah can approve I cant tell u but I know alot of car been on the road from 2WD to 4WD and approved by JPJ.
If ask runners to do it might inccur alot of money but if you do it yourself it's just a pain to send your car in and out of JPJ, puspakom and stuff. But once the approval have been aquired you wont need to worry bout road blocks and stuff.
Btw do make sure the workshop who do your conversion know's what they are doing, just cuting the chasis for your drive shaft might immediately make your car not road worthy pls do some research b4 doing so. Or better yet compare an ORi 4WD evo and a normak CK lancer see what's their main diff with their chassis and u might end up givin up on this project. :slug: