all depends on your listening tastes.....myself....300w is enough for a single sub......both jbl's wont hit rms unless they are ran at one or 2ohms.......so thats another thing to consider.......
do you think this would work? buyin a 600.1 and getting the svc 4 ohm model of the k. So it has a 4 ohm load and then the amp will put out 300 watts. By doing that if i want to upgrade later i have the option of having more wattage?
I've never heard somebody complain because they had too much power, you just use less fo the amp to get the desired sound level and the amp doesn't work so hard and sound good. You read all the time about people that don't spend the money up front and get an underpowered amp. They then crank them all the way up and push as much distortion as they do sound and the whole system sounds like crap. Do it right the first time and get plenty of power.
it sound's to me you may want to upgrade in the future or even sooner.
In that case it would be better to go with the 600.1 - because you can always turn the gains down and if you do upgrade you will still have a good quality amp
if you get the 300.1 you may be happy now but the JBL prices are so reasonable it does not cost that much to upgrade to 600.1 AND if you upgraded you would be looking at some sort of loss haveing a 300 mono amp that really cant drive a higher end sub.
if u get the svc 4 ohm model u r only gonna get a 4 ohm load. thats if ur just getting on sub. so if u r just getting one sub then ur only getting 150 rms from the 300.1 and then the 300rms from the 600.1