The 4000 sovran and the 4300 sovran were the same boat just relabeled in 2007. The overall length of that boat was 45 feet when you included the 3 foot swim platform and the 2 foot bow pulpit. It looks to me that they have simply changed the hardtop/windshield configuration and relabeled it the 4500 but it is the same boat. The 4000, 4300 and 4500 have all been IPS boats. I personally think that Tiara had to make the model name as large as possible for those boat buyers that compare their boats to Sea Rays and the other express boat builders out there based on price and length.