I'd go with the LTE over the S4, it's a bit softer.
As far as buttering the S4, it's possible, you may have "cheat" into it a little (a slight little hop, it's a bit to get the timing just right, but if you can you can butter anything anywhere - it's what they do to butter powder too - and if you get the timing REALLY good then no one will notice and you'll look like a boss for buttering a stiff ski). Again, I bring you to the D-Talk Spring Edit, first trick is a nose butter 3, and he's not that heavy either.