From the description you're giving, I'm guessing you're referring to producing electronic music. If so, then I can wholeheartedly recommend the N2X's for the job. I've heard the 2X's and I own the O-3's (the omnidirectional variant). They both do an excellent job for electronic music, which is mostly what I listen to (especially drum & bass). The clarity of the sound is startling at first, and I think the 2X's would help a good deal w/ your production.
I can't help you w/ the sub or the cabinets, but I can comment on the other parts. For assembling the crossover, if you haven't done it before or don't have any skills w/ a soldering iron, it's probably better for the Skiing Ninja to do it. Not too expensive, at under $100 if I remember right. Also, in regards to the crossover upgrade, it's well worth it. Especially the Sonicap Platinums as bypass caps. In my mind, the Platinums add quite a bit to the sound quality.
Hope this helps.