Oh yeah, keep the price in the $3K to $4K maximum range if possible.
It's been a while since I verified the power rating of the VT-100, so I trust that it is 100 wpc (as the name suggests). If that's correct, then you need to amend your thinking about moving from 100 wpc to 150 wpc, because that is only a 1.5 dB increase in power. Generally speaking, you need to double the amount of amplifier power (a 3 dB increase) to be able to hear any real difference in sound pressure level. Hence, you'll need to go from 100 wpc to at least 200 wpc, particularly if your speakers are of average efficiency (in the 86-88 db range). If you have very inefficient speakers (around 83-84 db, or lower), you may even need a 6dB increase (or 4 times more power than the original amp).
As noted above, when you start moving into high-power tube amps, you are also moving into high-cost territory, and usually monoblock designs. If you really like the sound of your VT-100 amp, it might make more sense to look for different speakers with high efficiency -- say, 90 dB or higher. Just remember that for every 3dB increase in speaker efficiency, you can reduce by half the amplifier power needed for a given sound pressure level. If you get speakers that are 6dB more efficient than your current pair, you will only need one-fourth the amplifier power to drive them to comparable volume levels.
Thanks everyone, it is not the that I want louder versus I want to make sure that the amp can control the large woofer 10" so maybe I just want to make sure that I have enough current? Also, what about the new CJ 140 power amp, 140 wpc stereo amp, is it any good? I am hearing it is one of the best CJ amps that the compnay ever made, I know probably a different sound then the VT-100.
take care about the Vt 200, I understand there are some stability issues. You might want to do a search on that amp, others have reported issues. I believe the problem comes from the bias scheme, it uses matched quads and only has one bias adjustment per quad.
Also, rumor has it that they are discontinouing the vt 200 in favor of the vs 220 moono blocks. This may adversly affect the resale value of this amp.