http://www.yamaha-motor.com/boat/products/modelhome/422/0/home.aspx
I have a YAMAHA SX230 HO and love it. The link I provide is for the AR 230 HO, and has the tower. It is a really nice boat with a ton of features. I have a 2005 and it has the two captains chairs. In 2006 they changed the design to include a head/changing area so the passenger seat is modular. The rear swim deck is really cool with built in seats and stereo remote. The 230 uses twin 1050 cc yamaha 4 cyl engines--very powerful and fuel effecient. It has twin throttle and tachs nice for low speed control. It is really cool to wind it out with both motors singing at 10,000 rpm. It is a "jet" boat so it is very easy to maintain.
Here is a great forum with tons of info.
http://yamahajetboaters.com/forum/index.php