There's a lot on this theme in other threads. When you consider a KPA or any other amp-simulator/modeller you need to understand the difference between these and a traditional amplifier wrt how and where the sound is shaped in your signal chain.
The KPA is designed to work with linear amps and speakers. That goes regardless of whether you've got the built-in amp or not. Traditional guitar speaker cabinets are anything but linear. In fact it is the uneven amplification of different frequencies that give guitar amplifiers and cabinets their unique characteristics. As the KPA is supposed to be able to replicate the sound of any guitar-amplifier it needs to work with power-amps and speakers that are as neutral as possible. If you hook a powered KPA up to a Marshall or Mesa cabinet it may sound decent when you use ditto profiles, but it will not be able to sound exactly like any of the traditional lines of blackface or tweed amps, and vice versa. Would you hook up a Fender Blackface head to a Mesa 4x12 and expect it to sound like a Fender, or hook a Mesa Trirec head to Fender 2x12 and expect the full Mesa experience?
For a modelling rig such as a KPA you are looking for full-range PA-cabs, stage monitors or studio-monitors, active or passive depending on which version of the KPA you have. Other cabs given the right wattage and resistance will work, but FRFR is required for the ultimate KPA experience.
heldal is half right.
The profiler works better with flat systems that do not add 'character' to the sound - unlike guitar speakers.
It does, however, work with either. You won't see the full benefit from your profiler, but there are many folks who are doing this and are very happy.
As for power ratings;
600W through 130W rated speaker setup means you can never, ever ever, push the volume above 2.5 (assuming the volume control is linear). You might run into volume trouble.
the 130W of two V30s is not a volume rating. The perceived volume is determined by many other things - so the volume you're used to hearing out of 2 V30s might not be there.
While a tube amp through 2 V30s can bury a band in the right context and position, a power-rack through those two might sound very, very weak.
In short, no.
You don't have to look for some higher rated speakers. The Profiler works fine with any speaker out there. To quote CK from this thread:
If you play at volumes that a tube amp would produce, you will not exceed the wattage a tube amp would put out.
While thousands of powered Profilers are out there, we don't even have a handfull of reports about blown speakers.
Ever cranked a 25W tube amp on a single 25W Celestion Greenback? Even that should be loud enough for most occasions 
My advice: Choose a cabinet that feels and sounds right for you, don't worry too much about the wattage. It was also stated, that there will be a firmware update to increase the visibility of the poweramp performance in the future. For more information, look right here.
As heldal and Quitty said above, many users prefer to use FRFR-speakers. As a guitarist coming from playing guitar speakers you might have to accustom yourself to using those flat speakers. Therefore you will feel more homely playing regular guitar cabs at first. I play a FRFR-cabinet and a guitar cabinet in stereo, which is a bit like the best of both worlds. But I grow fonder of the FRFR-cab every day 
It's far more precise and has a much better dispersion.
But back to the topic of choosing a 2x12 
Especially in the Fractal Audio Forums you will see people praising Port City Cabinets - the 2x12 OS (Oversize) cabinet seems to be a really decent choice. Often recommended speakers are two Celestion V30s or a combination of a WGS Veteran 30 and a WGS ET65.
For the most part, your ears will start complaining before the speakers start to burn out. If my 65w 6505 2x12 can get up to stage volume with the knob at 7... you should be fine.
CK did say, at some point, that they were hoping to add a "the power amp is currently putting out ___ watts" type of thing in the future, specifically for situations like yours. That was a while back though.
Well, guitarists have been known to like the sound of overloaded systems. Doesn't make it any healthier for the speakers, though.
130W isn't very loud when you're dealing with solid state amplification. As for sound, short of an FRFR solution i'd just go with a speaker you like.
130W isn't very loud when you're dealing with solid state amplification.
You may perceive volume in another way than I do, but I would totally go deaf if I would stand in front of a 2x12 with a wattage of 130W powered by a Kemper Powerhead
I'd divide the isue in two:
1. Burning the cones. The amp's nominal power is output when all the controls are up, volume icluded, and when the input is maximized. Usually a loud amp is performing at a very low steady wattage (5-15 W). We measured a mesa 100 W amp playing at extremely loud volume through a 4x12 and it was outputting a handful of watts.
So you can't certainly put the amp's volume all its way up with its input maximized with a 30 watt cab, but for regular use you should have no issues. Mind the cleans and their transients most, rather that heavily distorted sounds.
2. Getting enough volume. Talking about wattage alone won't give you any information about the sound pressure (volume) you'll get in the room. Several elements contribute to SPL, the most important at the same amp voltage output being the cones' efficiency (which is declared by the manufacturer): the higher the efficiency, the louder one Volt output by the amp will sound.
Summing up, while a cone's nominal wattage matters in terms of the maximum applyable power from the amp, if you want a louder volume choose cones with a higher sensitivity.
HTH 
A 2x12 will work just fine. When I had my Mesa 2x12 with V30s, I had my previous Kemper powered rack very loud through it. Never an issue. With that said, if you are using the higher gain tones, I've found V30s to be great but all of the profiles end up sounding the same. I am currently using a couple of Greenbacks and I notice a much better differentiation with the profiles on my new regular Rack. Either way, just use good judgement when turning it up. Good luck!
