KjuTiPaiNo you absolutely do not need an amp for this. I purchased this on the last drop, they sound absolutely fantastic with an iPod classic. You definitely will not go wrong by buying these. One of the best purchases I ever made on Massdrop.
KjuTiPaiNo you don't need an amp, but as with any HP a good DAC/Amp always improves the sound. I use my DT1350 with the Centrance DACport HD (the slim has been sold by MD in the past) which even allows one to explore DSD files as well as the many HiRes files available. The Tesla drivers in the DT1350 just come alive in an amazing way allowing every detail to be heard. http://centrance.com/products/dacport/
KjuTiPaiA) These are $10 less than all of the previous drops (including mine). Bloody tossers LOL
B) Just like any good headphone, these scale well with an amp/DAC. No, you do not need one per say (using these straight from my work Dell right now), but it definitely benefits them. I see 80 Ohm rating as on-the-fence mark.
C) These and Sennheiser HD25 line are kings of the on-ear-portable near-audiophile headphone pile. I travel with these work along with the mentioned CCE Slim DAC. IMHO Best bang-for-buck, build, and audio quality given weight and size constraints. If I ever had to get rid of all my gear and keep just one set up, this would be it.