I have seen two people post pictures of melted fog housings putting HID inside in the past 3-4 years. I don't recall in the headlight housing but since I don't have a 14+ I don't follow the thread linked above closely.
Stick with 35w...50w makes them way to bright and you end up blinding people. I have 35s and trust me, they a very bright! I have 50s on my high beams and they almost outshine my 40inch light bar.
from my understanding (and i could be looking at it incorrectly), there is no price difference between the two systems. my big reservation is that i have a set of DDM 55w HID's that are 6-7 years old. they are bright, but don't seem to be overkill by any means. i never get flashed with them. my belief is that the morimoto is of higher quality, but i don't want to be disappointed with light output.