Regarding integrating a sub- with a little time and effort with a sound meter and test cd you can do it nicely. Using a crossover and an active sub means less work for your 30 wpc amp since it will not see frequencies below your crossover point. You can also insert a relatively inexpensive DSP-based parametric equalizer between the crossover and sub to quell any problem bass frequencies that you identify with the meter/test cd.
Using this approach with an aleph P, aleph 30, bryston crossover and REL subs worked great for me.
Using this approach with an aleph P, aleph 30, bryston crossover and REL subs worked great for me.