The first example of Crespo's remarkable arranging skill is the famous Bach Toccata and Fugue in D Minor. A video of this arrangement may be found at the link below.
A second excellent arrangement of Bach's music is the also famous Arioso. I find this arrangement remarkable for Crespo's ability to space the voices in a way that creates the best blend on a piece that is seemingly simple.
My last example is the Overture to Nabucco by Giuseppe Verdi. I love the imitation of the tremellos and trills in the horns that sound nearly identical to the original string writing.