Getting at the Galaxy S4's guts is a cinch. That's partly by design: The back cover pops off so you can replace the battery without any tools at all. From there, taking everything else apart by removing just 11 Phillips #0 screws.
On the motherboard are found the following:
Snapdragon 600 APQ8064T 1.9 GHz Quad-Core CPU
MDM9215M 4G GSM/UMTS/LTE modem
PM8917 power management module
WCD9310 audio codec chip
WTR1605L Seven-Band 4G LTE chip
PM8821 Power Management chip
[video=youtube;oUV6PSv-CZE]http://www.youtube.com/watch?feature=player_embedded&v=oUV6PSv-CZE[/video]
The only black marks against the device are the fact that the glass is fused to the display and display frame, which increases the cost of a replacement, and that getting at the screen means taking the entire handset to bits.
iFixit gave the Galaxy S4 a repairability score of 8, with 10 being the easiest to repair.
iFixit