I've got the same cross spokes on my Brera and have been thinking the same as you for the last couple of years.
I use a set of 159 17"s in the winter (just clear the calipers) with Winter tyres from Oponeo as they're much cheaper and have more variety than the 18"s.
Thought lots about the pro-drive 19"s and even sent a message to Team Dynamics (Rimstock) asking about minimum order for a production run but never heard anything back. I'd be tempted with another light weight 19" wheel although common perception on here seems to be that the 18" wheels offer the best ride.
I also looked at the 19" 159 Ti wheels but even second hand, they're still not loose change and heavier than the 18"s negating and un-sprung mass benefit.
If you do splash out on the Pro-drives, you'll probably get a fair chunk of your cash back if you needed to sell them on second hand. A 'well' used set went on eBay last week for over 600gbp without tyres.
So, it very much depends on what you're looking for: performance, style or (less likely) economy. As mentioned before, you'll realise much more performance for you money looking at things like suspension, brakes and exhaust etc (especially for nearly 2k!) but my goodness, those pro-drive wheels look awesome!