Hi,
I built a pair of full ranger based on a different FR driver(made in China) 4" and housed in a sealed enclosure. The enclosure size is about 5 litre. I paid less than $100 for this pair of drivers.
I was surprised the size of music sound stage it can throw out for such a small speakers. The only drawback is it cannot handle power. Most full ranger of this size cannot handle power, it tends to distort, there maybe an exception the Alpair range of drivers.
I would like to try the Alpair CHR70 it will go straight into my existing enclosure, you may like to try them I believe the new mark III model is very good.
Cheers. Enjoy your speakers.