i traded my P3D- for an X P90DL (rather, I sold the former to buy the latter) and also felt like the 3 is faster. Estimated 0-60 times are 3.5 for the 3 (at the time I had it), and 3.0 for the X. I have recorded run times on my dragy and the fastest I got was 3.53 for the 3 and 3.63 for the X in Ludicrous Plus mode so not only does it feel slower, it actually is. It's a shame that I have to spend 30 minutes "warming" up the battery when the power on the 3 is instant and always available.
the battery chemistry is different between 3 and s/x.
3 battery is more advanced and the cooling ability is way superior than s/x