WAF. And where are you going to build them? Clear it all with your family first - that's the MOST important consideration. With support, joy - without support, pain and more pain. Trust me on this.
If you decide to procede: ScanSpeak makes a lot of different speakers, but I expect that they don't all play nice together. If you get good advice and buy high quality drivers, chances are that you are building to a very high standard. If you buy high quality caps, like styrene or teflon, ditto. But - you may not be used to sound of that quality, and may not recognize it. The sound should be smooth and get better hour after hour.
Then it's 'only' a matter of cabinets and crossover design. As mentioned, expect to spend a lot of time, years, before it sounds as you want it to. But it's fun, it's educational, and you MAY end up with speakers that you couldn't possibly afford otherwise. That's what happened with my modified ESL speakers, my DIY electronics, and my DIY turntable. I was lucky, and I planned and calculated and planned some more.
Remember: WAF, WAF, WAF. Then you can start planning.