I had mine re-mapped and CDA'd by angeltuning. I never got it to a rolling road but it made a huge difference.
Several people have reported that 153bhp is possible, although you may need a CAT back, like Supersprint and possibly to upgrade the fuel pump.
In terms of CDA: Technically it should be better as it sucks cold air in, whereas even cone filters with a cold air pipe won't draw in cold air in a traffic jam.
However, getting the CDA to fit well into a older Barchetta was a pain and so it may be better to get a GSR kit/re-map fitted at Red Dot. Make sure you've had your exhaust done first and then you can see the difference on the rolling road.
As I said at the beginning, it made a huge difference in terms of drive-ability and the car picked up better in higher gears.