I just installed the Wetsounds Doubleup and am pleased with the sound quality. The question is... Wetsounds tecs say that I should have at least 150 RMS per speaker. They suggest their SNY4 but it only has 125 RMS. I have 100 RMS now and wonder how much better they will be with 25 more RMS and if I should consider going with a JL HD600/4 that offers 150. Net net will 25 and or 50 more make enough difference to justify the additional $$
Both amps are great. I think that the wetsounds ratings are conservative and that the Syn 4 would do the job. To get the most out of the Double Up package you will want to use a 4 channel amp at a minimum. This will allow you to select different crossover points for the pro 60's and the mb-8's. The mb-8's will be crossed over lower than the 60's.
Have you looked at the Syn 6. I know that Tim from Westounds swears that this amp is the best possible single amp solution for the Double Up.
I'd personally go with a Wetsounds amp. No doubt the amp's preform and the customer service is unmatched.
That JL amp is sweet but you could get an Alpine PDX 4.150 off of Ebay for about $350. They're sick amps too and usually come out with a higher certificate than the rating. Another great option would be the SYN 2 run at 2 ohms and show em 175 watts per. Don't under power, OVER POWER!
When running a speaker system with more power. You gain "headroom" This allows the amp to not work as hard to get to the volume level you want. If you are happy with the output now and sound quality. It may not be something you need to bother with. But I can tell you with 100 watts. You are not using the speakers to their max potential. So upping the power is going to get you more output and better sq. The SYN-4 is our base recommendation. As it will do 125x4. Which is a little under rms ratings but still very solid power and as you can see with only 100 watts. The system will still rock. So more power than you have now will be even better. But, the best amp on the market for the Double Up is our SYN-6. As it will do 200x2 and 155x2. Since it is a 6 ch amp that can bridge down to a 4 ch. So it offers more power than most conventional 4 ch amps.