I'm still learning about the trick of working with the 1911. I've seen some video off competition shooting and it looks like they are using a .22 because there is almost no recoil. Will changing the spring do this and what is the downside of doing it.

It looks like they're shooting .22's, because in many cases they're shooting very light loads.
Then too, these people know how to really hold the gun and fight recoil.

Changing recoil springs is not something you really want to do unless there's a genuine NEED to do so.
NO ONE knows more about a gun than the maker, and they spend millions of dollars designing the gun and balancing everything out so it works properly.

In spite of this, people with no real idea of the forces involved seem to think changing the recoil spring is no big deal, and that they somehow know more than the people who built the gun.

Changing the spring to a lighter or stronger tension spring can have a major effect on the gun, from unreliable operation, to battering of the slide and frame, to cracked slides and frames.

In short, unless there is a valid reason, don't change the spring tension.

What you are seeing is people that are using lower power ammo, most of the time hand loads.

16 lbs is the factory specs for the recoil spring.  If you go to a lower rated recoil spring and still shoot factory ammo, you could develop cracks in the pistol from hammering the slide back all the time.

Unless you hand load and have someone to help you determine what spring rates will work for your hand loads, don't mess with the factory recomendations.

Also I should point out that the people you see on the televison in competitions have sponsors to help with the cost of new parts.

In short you will wear out the pistol and even make it unsafe to shoot.

Different 5" 1911s ship with different weight springs which I've always found a little odd. Wilson CQBs ship with a 18.5#, RRAs with a 16#, Jardine ships his Valtro with a 17#. I always shoot full power loads and for the most part have defaulted to the 18.5# recoil spring when it needs to be replaced in all my 5" 1911s.

Day jaw voo all over again.  There is an entire forum dedicated to springs on the brian enos site.  www.brianenos.com  Hope this answers some questions.