The smaller driver is how they get that accuracy up IMO. The range is limited so it has less to do, thus sounds more accurate over its slighly narrower range

Less extension is the expense of that accuracy though.
In your range, the Ascend CBM-170SE would be a good choice and the CMT-340SE is just a bit above that budget, but would be an even better choice for the additional output and extension. They are not entirely neutral sounding though; they lean a bit toward bright, but are a very good sounding speaker.
http://www.ascendacoustics.com/
If you can build your own cabinets, the GR A/V-1s are +/-1.5dB over their range and are good to 60Hz (mine are tuned to 50Hz and give up some output for extension). They are extremly neutral sounding IMO. Building your own cabinets, these would be well below $500/pr finishsed IMO. (see sig for link)