If you're dropping pulley sizes you definitely need to address cooling sooner than later. A stage 3 intercooler or equivalent. A phenolic spacer for the intake manifold helps keep the engine heat from transferring to the intake. And you don't need to port the intake manifold, just the head and sc if you choose. Most porting is done on the exhaust side(which is the restrictive side) to match the intake. You can however polish the intake manifold while you have it apart to do the dual pass endplate. You can get the SC ported to use the larger ls4 throttle body and move more air, which I think is especially beneficial if you're going to a smaller pulley. So if it were me, and you wanted more oomph and to maintain driveability:
Phase 1:
Address timing issues
60# injectors for 93 or 80# for e85
If going e85 then boost reference fuel pressure system to help with idle surge of larger injectors
Dual pass endplate(you can diy this for cheap)
Phenolic spacer
Option b tank
S3 heat exchanger or equivalent
2.8 or larger pulley which requires all of the above(2.7 requires cams according to ZZP)
SC porting(Category V Portworx is highly recommended and does excellent work, Josh Billheimer with them can also do your head, but I would save that for phase 2)
LS4 throttle body
AEP Wideband o2 sensor, needed to tune(30-0300 seems to be the sensor of choice on the forum)
Something that you might also look into, which I'll be doing, is adding a "interchiller/killer chiller". You keep the ac compressor and run a brazed plate heat exchanger to super cool the intercooler air temperature. Can't speak on how well it works yet, but if it works for the Dodge Demon why not the DF Goblin? Haha. Here's a link to diy if you're interested:
W211 AMG - The Thrill Chiller V2 (Killer/Inter DIY) - Recently I have decided the price for the chiller kits are absurd, these are 100% packaged kits with no custom parts marked up a ton so I have put together a full parts list for any one that would like to do this themselves. Some credit to...
mbworld.org
Also here is the screenshot of the zzp stage 3 kit which shows how you should select the pulley size.