You could drop pulley size first, but if you do until you get it dyno'd and programmed I'd run it easy, baby it even.
If you get the thermostat dropped to 180F your primary and secondary fans won't come on when they need to, but the motor should be cooler from the more constant coolant flow, so you should be ok there.
Dropping the plugs to one heat range colder should not cause much of an issue, but again if you are doing all these things I'd get the things you need ordered, then add them all at once, then drive it easy to a place to be Dyno'd, just make sure to tell them everything you have done.
With the pulley, I'd not go lower than a 3.6", dropping .10 inch drop should add 1lb of Boost, so a 3.6 would add 2lbs of Boost.
You could go with a 3.4", but I'd not go any lower, that would add 4lb'* of boost, and with the heads/LIM porting I am guessing you will have 35-40 or more WHP, 25 WHP or so without the LIM/Heads ported.
intense makes a good pulley, but you may be able to get a cheaper yet still decent one from ZZP or 3800performance'* site.
Here is a good tool to use to pull the pulley.
You may be able to rent one though, so check into seeing is Autozone or somewhere rents them first, then again you may not be able to rent one from what I am reading on the e-bay description.
" If you ever need to replace the bearings in a snout, install a new snout seal because it leaks, replace a pulley, upgrade a pulley, etc you will need this tool and typical parts stores will not have one."
I have not replaced, or changed a pulley size yet, so maybe somebody else has some feedback on that.
ZZP supercharger Pulley Puller Removal Installer Tool Eaton M90 M112 M62 | eBay
When you change the pulley I'd get a Goodyear Gatorback Supercharger Belt, unless you already have one.