Drow are not "low level" monsters. They are "high level" monsters that should strike fear into the hearts of adventurers of any level..
I would totally ignore the CR 1/4 "soldier guys" [I guess?]. Your "basic/low level drow shmo" should be the CR 5 guys.
But it's so much more fun to kill PCs on a budget of 1000 XP. The mooks are almost as good as the elites if you use them right, and a whole lot cheaper.
Among other flaws in the official system, players advance in level more quickly when they have equivalently hard combats against fewer foes as opposed to more foes.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.