Bora and Khamsin are both great, but are not from the bi-turbo era as per the original question posted! I wish I'd not sold my Khamsin a few years ago, and not only because since then it's gone from about £30k to £150k.
For me, the Shamal is nicer to drive than the Ghibli Cup, largely because the seat is better, as is the driving position in relation to the steering wheel and pedals. I always found the clutch action/position a little awkward in the Cup. As for performance, there's nothing in it really. Though the ground clearance on the Shamal is poor, so you tend to back off when driving spiritedly along an undulating country road as the centre exhaust section scrapes in the dips.