140mm lower than standard are you sure dude that is way low, well actually you would be dragging a fair bit of stuff :uhh:
How much do you want to spend is the question to ask your self, bilsteins are about $900 for the four, not to hard pritty good for street use. You could get KYB's for a bit cheaper don't know what these would be like though, they are about $750 for four.
If you lower it a fair bit you are going to need alot of caster and camber dialed in.
What sort of bushes have you got.