You will LOVE the Wet Sounds Syndicate series amps. I promise!
Evilone, your right. HAHA. Since he is running the 3-Some. The SYN6 is the only amplifier that is truly built to properly power that set up. With the ARC KS, there is not an amp that can run the 3-Some. So it would leave having to run 2 amps like the KS 300.2 or under powering the set up with the KS 300.4
Same thing with the Jl m6600. That amp would be doing 150 watts to each. Which would be ok on the 80's but a lot less power than the 485 can handle and needs, only 150. (80's are rated at 200 watts rms and the 485 is rated at 300 watts rms. But I like to run more power than that to the 485)
Same thing with the JL 450.4. It would be 300 to the 485 but only 75 to the 80's.
The syndicate amps are very efficient. So less heat and less current draw. Which means more playing time and less strain on your charging system.
We use class H for the power supplies which is a switching power supply. It is unique in that it has the efficiency of the class d's and full range class d's but has the sound quality of a class ab. Where most class d and full range class d amps have higher distortion ratings.
JL has a new full range class d amp. HD 600/4 that does 150 x 4. 150 to the 80's and 300 to the 485. So that line is not as much power but closer to an apples to apples. I believe the HD 600/4 is pretty close to the same price as the SYN-6.
With the SYN-6. You will be doing 200 x 2 to the 80's and 600 x 1 to the 485. A true 1000 watts on the tower.
You are right on with the SYN4 on the inboats and SYN1 for the XXX.
You could also save some money and still have a ton of power if you went for the SYN-6 running the in boats and XXX. The SYN-6 can do high pass or low pass on chs 5-6. So you would be doing 60x4 on the XS-650 and 600x1 at 4 ohms mono on the XXX. (it is a dual 2 ohm woofer, so wire it in series) If you put that woofer in the slot loaded ported box. That 600 watts is good power for it. We have had a ton of guys doing this exact set up.
2 amp system. SYN-6 on the 3-Some and SYN-6 on the inboats and XXX woofer.
Let me know if you have any other questions, happy to help out.