Here are a couple of suggestions.
Fot the tower, the Wetsounds coaxials are a good choice for surfing. For $50 more you can get the identical speaker in a Wetsounds pod that has far more displacement and has much more midbass as a result. Besides, you want to avoid a soft polished aluminum pod from China. They will dull rapidly and the effort-intensive upkeep can be avoided.
Do not buy a JL Audio amplifier from an unauthorized source. There is zero support and zero warranty as clearly stated on JL's site. If they are not displaying the full JL Audio logo in graphic form or are not listed by JL, they are not a legit dealer.
JL Audio amplifiers are awesome. The power is great for the inboat coaxials but a bit light for the demands placed on a tower speaker. Depending on your time table you might wait for the new JL Audio 8-channel so you can bridge 4 into 2 for the tower. Or, you could run a passive sub and split the duties into two amplifiers.
Also, look at the Wetsounds Icon8 tower speaker. It's a conventional non-HLCD in the same size pod as the XST-650 but with nearly double the cone area.