I'm thinking about having the gas block changed on my budget AR. My only fear is that it's been reliable so far and that if I mess with it, then I might screw something else up on the rifle. I guess I just don't know enough about them to trust myself not to fuck up a perfectly good rifle... Thoughts on this?

If it ain't broke...don't fix it
But if you're set on something different, and you're just wanting another gas block on it... you will just have to adjust it until your gun likes the amount of gas coming out. What's the reason you are thinking for changing it?

I would think that you would be okay as long as you don't open up the gas port itself?

Won't matter unless you instal it wrong

As long as the new gas block is installed correctly, your rifle will still function perfectly fine.  Installing a GB correctly isn't exactly rocket surgery.  I guess the more important question is, why do you want to change the gas block?

I'd like to free float the barrel. Not for the added accuracy, but just because I kind of like the look and would like to primarily run flip up iron sights but still be able to mount a scope when I please. I only have the one rifle and limited funds.

Just to put it in perspective, it's a DPMS Oracle, so I mean that should tell you something about my financial situation... I mean in a couple of years here, when my school bills are paid off and I have a little more dough to throw around then yeah, I'll upgrade to some nicer stuff but for now I figured for about $200 I could free float it and slowly add shit as I can.

Edit: I should add, that I am aware of gas block height front sights. It's just that it seems like the options are limited from either fairly expensive to very cheap and nothing in between, plus there's the whole issue with making sure that it really IS the correct height... Who knows, I just see a lot of people changing parts on these guns willy nilly, but I always am a little anxious that every time I mod one of the guns I own, I'm basically going to screw the reliability, which is annoying to say the least. I try to keep guns as factory as possible.

No.

It shouldn't change anything if you install it correctly. The easiest way is to get a cheap gas block like this http://www.primaryarms.com/troy-industries-low-profile-s-s-gas-block-750-set-screw-style-sgas-a4l-00bt-00 and a rail that'll fit your stock barrel nut http://www.primaryarms.com/srai-sr1-10bt-00_2

Nothing wrong with that.  Get a low pro gas block and a rail and go to town.  Shit, I don't own a single "factory" rifle, all having been assembled from parts by me and none of them have had reliability issues.  Like I said, it's not rocket surgery to properly install a gas block and if you're that worried about it, have a gunsmith (like ADCO) swap out the parts for you.

Don't do anything now.

You have other priorities 

Agree with this. If you have pretty limited funds, there are better choices you can make with your money than upgrading your AR for a "cooler" look. Enjoy what you have now, and you'll be in a better position later.

You can always buy parts as they go on sale too, just because you have FF rail sitting there doesn't mean you need to install it. I have a FF rails laying around and other projects that are not really priority, just if I see a sale, I buy some parts.

I just built a 6.5 Grendel and it took me 2 years to complete, because I would only buy the parts I wanted when on sale. I still don't have the rail I want, but one of those FF rails I have laying around will work for now. I have a 458 Socom that is just waiting for the barrel and bolt.

This may work for you  without changing the gas block.

From Windham Weaponry for $109.95

"Diamondhead VRS Drop-In Railed Handguard for AR15/M16

...This handguard set mounts directly to your rifle’s existing handguard cap and Delta ring - just like standard handguards. ... "



https://shop.windhamweaponry.com/collections/handguards-grips/products/hgd-dh-2001

I had a DPMS Oracle not too long ago. I know what you mean because I didn't like the handguards and weird railed gas block it came with. Just replace it with a BCM gas block (lo profile .750 I think) and get a rail (m lok, key mod, your choice) you can re- use the carbine gas line and good to go. This could be up to $250 for parts depending on the rail you choose of course. I picked a 15" Troy which was around 175, the gas block was 45 or so .. have fun