I currently have a Rotel stereo amp, a TLC-1 preamp and NHT 0.5 front speaker.
Now I'm getting a HSU TN1225 sub, but not the amp. So I think that I have 2 options:

1. Buy a good amp with crossover build-in, and use the ROTEL for the sub.
2. Buy an amp with crossover build-in to drive the sub.

So, my question is, which one would be better? and any good amp to recommend in either case? I was looking at NHT SA-3, but cann't find many stores having it.

Thanks ahead!