Some people prefer "nerve-wracking" because they associate it with wrecking - the wording "nervous wreck" is recorded as early as 1871.
It was always likely that rack and wrack should overlap. Wr- at the start of a word has been hard to pronounce from the time when w began to sound in Old English as it does today.
Other Germanic languages do not have this problem as they pronounce wr- as vr-. So does the Scots Doric dialect.
Some experts believe that increasingly either the two consonants were reversed (as in "Rwanda") or the w was silent. The latter is certainly what happened from the 18th century on.
Like the pronunciation, the meanings of racking and wracking are hardly far apart.
In the First Folio edition of Henry VI, a character is said to be: "Like a man new haled (newly hauled) from the Wrack."
Surely, "from the Rack"? Some later editions thought so. Or is it really "Wrack" meaning "punishment" or "destruction"? We cannot tell. And Shakespeare - who meant it to be said, not spelt - may not have cared.
Did Shakespeare mean Rack or Wrack - or didn't he care?