I've been considering changing a couple things on my R1 1911 5" Government (.45 ACP), one of them being the barrel, which I'd replace with a threaded unit. Might as well go threaded, no reason not to. However, I have a couple questions regarding this.

If I did swap to a threaded barrel, is suppressing a handgun as easy as just threading on a suppressor then going on your way? I know with rifles there's some tweaking to be done, particularly the gas system. So, if there are any, what would need to be tweaked on a 1911 handgun? Recoil spring?

Second, and this is the primary reason I'd like to swap. I'd like to have the option of running +P ammunition in my R1. Remington doesn't recommend doing so, however. Would changing the barrel, and perhaps a recoil spring, alleviate this issue? If I'm not mistaken, the majority of the pressure is handled by the barrel and chamber. It did cross my mind that the breach face on the slide wouldn't be too happy with me if I did that, but I have also seen where someone dropped in a .460 rowland conversion kit using the stock slide, seemingly without issues.

Thanks in advance.

Remington saying no plus p is legal cya. Any modern 1911 can handle it. Yes add a huge weight ( can) to the end of a mechanism designed to operate via recoil force and it may need tweaking.
And most importantly you are not likely to find a replacement barrel that does not require fitting to work optimally.
Rather than take a $600 Remington and drop $350 or more in work to fit a threaded barrel etc, makes more sense to just buy a threaded gun

You're absolutely right, it would make more sense to just buy another handgun with those features. I was considering making the changes to my existing pistol more as a project than anything. Something to do, something to keep myself busy.

IIRC Most cans make stock sights useless.

You are putting lipstick on a pig.

Having said that, what about a $500 1911 for this project? A Rock Island 1911 or something else similar? That way if there's some serious reclamation work that needs to be done, it won't be on a $1000 1911.

I'm not certain, but I wonder if a slightly lighter recoil spring wouldn't be needed after adding a can to a 1911?

Properly fitting a 1911 barrel is almost a black art.  I’d leave it to a pro.

Your gun can handle +P. I would replace the recoil spring with a 18 lb recoil spring and maybe a shok buff.
Not much is gained with +P ammo in a 45.

Suppresors are only worth the money in .22 and .300 black out.
All other calibers , you will still need to wear muffs when you shoot.
Alot of expense and paperwork and you still don't get the almost no noise you see in movies.

Cheap easy thing you can do with your barrel, check the fit of the barrel bushing. If it's loose to the barrel or loose to the slide,
You can get alot better accuracy with a well fitting bushing.

And it doesn't have to be so tight you need a wrench. Just snug.

Measure the inside of your slide and outside of the end of your barrel with calipers and give EGW a call.

Not sure how you arrive at that. I shoot my 9mm with no ears & use subsonic ammo.

You also misspelled "suppressors"..........  

You can find eccentric cans that hang below the barrel.

They are harder to design and build and they usually cost more.

Or you can just aim through the can.  Works fine.