I suspect you would be looking at a new power steering system as the later cars were significantly different in that area, a by-effect being active lane assist.
They no longer had a shaker in the steering wheel, instead using feedback through the column - meaning you didn't have to opt for the ugly 4 spoke to get lane assist.
To be honest - In my opinion any form of lane assist is something I'd switch off on a D4, just leaves you feeling detached (and sometimes confused, when you thought it was turned off but you caught the stalk) but isn't good enough to be really useful