I personally wouldn't bother, the car already has pretty rubbish ground clearance - I'm always catching the bottom of the front bumper on kerbs and on steep slopes.
Are you wanting to lower the car for aesthetics or handling? The car does have a bit of a gap between the wheelarches and the wheels and I suppose they do look a bit better on lowered springs, but I don't think I could put up with the disadvantages. I find that the handling of the standard set up is excellent (I have a cloverleaf, so I don't know if it has the same suspension as yours) as long as you have decent tyres and everything is in good nick - I've done a few track days and am still amazed at how adjustable the car is and how well (and quickly) it corners.
If you really want to lower your car I would recommend Eibach progressive springs - they're probably towards the top end of the price scale but I think they're superb (I have a set on my 33 and the ride is not too harsh and the handling is great).
I have also heard thet the Anti roll bars can be changed for Fiat Coupe items which are thicker. You will need the clamps that hold the bar to the body as well as different drop links. This should sort the body roll issue, although personally I don't find it too bad.