You can always solve this by having ''used cars'' that display worse properties than the same cars that are brand new, as well as introducing rent for housing. Drugs and illegal weapons should have prices adequately adjusted as well, so I don't see the whole ''waiting for a week'' issue.
A few of us played in a server that had a ‘realistic’ economy. It was still much easier than real life to get what you wanted, but it was calculated that it’d take days of playtime to afford even the cheapest vehicle.
I have no intention of spending days worth of time to be able to afford anything. Casual players would be completely unable to compete with those of us who are on for hours each day.
Anything regarding the economy needs to be well thought out, since it effects every single element of the server in some way - such as preventing players from being able to roleplay the characters they want to for hours, days or even weeks in the extreme.
Anything that increases the time between joining and being able to roleplay your character is a big no-no for me.