Compensated is fine as long as you never plan on carrying it regularly. It'll destroy your night sight when you fire it, and the best defensive pistols aren't usually compensated. For range and fun only? Go for it guess. You can always get a regular Glock 19 barrel too and then have it un-compensated as well. Best of both worlds.
Most Glocks I leave stock, but polishing on bearing surfaces helps if you're keen on that, and a Glock 3.5lb. connector is nice for a range pistol too. I'd leave the recoil springs alone unless you fire weak handloads, weak target loads like I do, then you may find a steel guide rod and various spring weights handy. But with a carry gun, keep all this stock.
For all Glocks: Sights? Always change those, all my Glocks have aftermarket sights. I like Trijicon for carry, Meprolight adj. for target shooting. Both use tritium. You could use the ext. Glock slide release if you like, but I'd be wary of aftermarket anything save some of the steel guide rods and sights. Generally, Glocks work best stock. They just do.
But then again, it'll work fine for range use without being compensated too. Get some good sights and go for it. I have several Glocks, not a one is ported. For target use, I put a 15lb spring it for light loads, and I carry the same G17 or G17L using the factory recoil spring with regular loads. No problems.
I have a G17L, a 6" long slide, and it's a tack driver as far as Glocks go. Now that one and the G34 are both 9mm's that have large cuts in the top of the slide that allow for ported barrels already. The 17L stopped coming in C model a long time ago due to issues it caused with the sights. Aftermarket Trijicon or Meprolight may alleviate this problem, I don't know. Not sure if 34 comes in a C model. Regardless, they have the cuts and you can have a stock barrel or aftermarket barrel ported to work with these openings. You'll have two barrels, one compensated and one not; the best of both worlds, only in a longer pistol.
Lots of options, but they work best as stock as possible if you ever plan on depending on it. Good luck and Happy New Year!