for a jl 250/1 1 12w3v2 or 2 10w0's?
 

I had 2 10w0s like 5 years ago with an alpine amp, I was happy with it. But for this amp wich would give a louder cleaner sound? 1 12w3v2 or 2 10w0s?

The 2 10's will generally produce more SPL than on 12, however it is a little more complicated than that. Are you going to used a sealed or vented enclosure? There is more surface area for 2 10's combined, therefore it's physically easier for them to produce a higher SPL than 1 12.

As far as the "cleaner" sounding part. I smaller driver will tend to be quicker allowing that somewhat tighter sound. However, with a really good line of subs, such as the w7's, there is very little difference in the quality of sound from the 10 through the 13.5.