In my opinion, techno and dance music, is loud and bass driven music, so you would want a system that had plenty of power, especially low end power. I would also go with a balanced system over a single ended system. A true balanced system should give you an extra 6 db of gain over single ended. This can be huge when pushing the limits of your rig.
The techno that I listen to, the low end is very prominent in the 30 to 60 hz range, but bass that low can be difficult to control so I would recommend using multiple subs and since the low end in techno is also very impactful (you can feel it as much as hear it) I would say multiple subs with drivers 12” or larger.
This will be rather controversial but I would also look into a good electronic crossover or speaker management system, aka DSP. A good speaker management system will help improve the systems impact especially at lower volumes and improve the mids and highs in your main speakers by reducing the amount of low end that they need to reproduce. If your mains do not have to reproduce the low bass you no longer need such a large amp for the mains nor will you need large beefy mains, you would have many more options to choose from including book shelves if you so desired, which could help in reducing over all system costs. Another advantage to speaker management is that it gives you an easy way of adjusting the volume ratio between the lows and the mid/highs which can help when dealing with those annoying variations between recordings.
With a good sub system and speaker management your main speakers and amp/s can be pretty much whatever you want them to be as long as you can insert the speaker management between the preamp and the main amp so you would either need separates or an integrated that has pre out and in.