Originally Posted by willyt
a big consideration is how you'll be using the boat. the 5.7 ilmore may be enough for surfing, recreational wakeboarding, and skiing, but if you'll be doing any footing, heavily ballasted wakeboarding, the 6.0 LY6 that the 2008 has will be really nice. also, i dont believe the 2011 has a trim tab, so porpoising may be an issue (or it may not be - i've never been on the water in a 15).
Yes, the X-15 does have a little bit of a porpoising issue at a certain speed and depending upon how weight is distributed in the boat. The attitude adjustment plate is also useful to lower the bow if you are going to hit heavy chop. You can use it to lower the bow and split the chop taking less impact on the hull than if you hit it further back on the hull (when the bow is up higher) where the dead-rise angle of the hull is less. Since we don't water ski, it is the most common reason we use the attitude adjustment plate.
Someone coming from an I/O may not like the inability to adjust the bow rise without the attitude adjustment plate.