I've used a TDC-Technologies CR-Plus unit ( TDC PowerBoxes
) on two 147's and my current Giulietta JTDm. It is adjustable from '0' (does nothing) to '15' (rabid bull with Wasabi up it's backside). It's been excellent, but I've been intrigued by the reviews of the Spider kit ( Alfa Romeo
) which learns from the engine and adapts to the driver's driving style.
The big differences between plug-in boxes and ECU remapping are that a good ECU remap can be tailored to meet the specific requirements of the owner, but on the other hand a plug-in box can be removed without trace when your car goes in for service and potentially transferred to your next car when you trade up.