What an astonishing post Symes! You've obviously never driven properly set up SU's. Certainly in the UK, advertising for 4 barrel carbs relies on people with defective or poorly set up SU's failing to realise this and instead spending money on unnecessary new equipment. There is just about an argument for changing to a 4 barrel carb if the requirement is to increase air flow rates at very high rpm. But you could equally argue that the correct answer in this situation is injection. For low throttle running SU's will invariably produce a result equal or better than a 4 barrel and are considerably easier to set up to the particular engine.
If you have a bare engine with no inlet manifod, then by all means fit what you are used to. But if you already have SU's then either overhaul and set them up properly or go for injection!
Chris