Liszt hasnt any good technical etude.
..?He has the best probably.
That a piece is very hard, doesnt mean the piece itself boosts your technique. What i mainly experience with liszt's etudes, is that you need to do alot of etudes for being able to play them. But that means i dont get technique from HIS etudes, but from the supporting etudes....
One word...Hanon!Kylie
Ah, what you didn't know is that he wrote ten books with technical excercises, written for building technique, scales, finger independence, octaves, jumps, thirds, basically everything. You should look them up. They're rather like Hanon, but 1000000000000x more useful.