A 16lb spring should be fine for a 5" 1911 running factory ammo.
Yes, you CAN get a softer recoil pulse from increasing the spring poundage....but (here is where it gets sticky) you do risk the chance of losing some reliability. The 5" 1911 was not designed to run a higher poundage spring, so your results might vary.
You might swap it out and it runs fine...you might not. You will have to test all ammo you plan on running to be sure. Plan on the pistol being harder to rack the slide, too.
On a 5' 1911, you should not have to increase the recoil spring poundage to ensure reliable feeding. Some will say that if you are getting failures to go into battery, you need a stiffer spring. Well...maybe...but chances are there is something out of spec on your 1911 besides the spring.
Recoil springs do get lazy...but its usually after a very long life and tons of shooting. This is NOT something you should have to race out and replace on a fairly new 1911.
Yes, many smiths will advocate increasing the recoil spring weight on the shorter 1911s like Commander and Officers Model length guns. This is done mostly to help feeding due to these model's shorter and faster slide cycle. Usually, you only need to go up 2-4 pounds and you have to be careful or you'll turn those guns into jam-o-matics if you put too strong of a spring inside. I have had to go up in spring strength in my old Colt Combat Commander, due to its failures to go into battery at time and it DID help things.
But on a 5" 1911? Never. Unless you are using it for competition with specially made loads (usually downloaded) then you really do not need a stronger recoil spring than a 16 pounder.
None of my 3 5" 1911s have a stronger recoil spring than a 16 pounder.
One thing you will find about 1911s is that yes, many makers make tons of accessories for these guns. Not all work as stated, many are unnecessary and some will turn your reliable gun into a nightmare. Be careful before you start replacing thing randomly.
Another thing you will find about the 1911 is that there are no shortages of "gunstore/range experts" that will be glad to tell you all sorts of stuff you NEED to do to your gun. Some give good advice...others...well...
- brickboy240