The 20 has 3 (fixable) defects from the factory.
1 - sights are plastic
2 - barrel is unsupported
3 - spring is too weak for full power loads
You can certainly shoot it as is.
I know its a old post... But it brought up some good points, with the increase in 10MM popularity.
Mike brings up three big points that should be addressed.
1) Good after market metal sites are something most change.
2) 6" barrel seems popular as do std length offerings from companied like Storm Lake, Lone Wolf, KKM and Bar Stoe. KKM advertises "fully supported" barrels.
3) A Metal Guide rod and custom spring weights are cheap and easy to change!
Lastly, better triggers as mentioned many times cannot be made to what a fine S&W or tuned 1911 can be, but are entirely shootable.
CW