We have member named Liam who is based in Italy and well-versed on Mangustas & Leopards. Hopefully he will chime in but in the interim, use the search feature on YF for discussions on these brands.
Gary, here’s a thread with some observations on Mangusta… https://www.yachtforums.com/threads/mangusta-70-80ft-1996-2004-advice.36869/
Sunseeker was a more production product, and with shaft propulsion or surface drives available. Most of the 108 Predator (12 made) are shaft drives and do about thirty knots. Mangusta and Leopard had jet drives, and apart some speculation builds where custom builds inside. These usually have top end speeds in the high thirties, subject to engines installed. Mangusta and Leopard change is not only in woods and furnishing, once you start to see a few you will start to see differences also in layouts. Mangusta has also the 105S or 107 raised cabin saloon version, which might be an interesting choice if you want more comfort. Once you are looking at Sunseeker I would also put the Pershing 108, surface drives and forty knots performance. If you are med based you could also see the Cerri 102 Flying Sport, and or Italcraft 105.