Assuming I can only fit one small radiator and no shroud in my case..

...and im too lazy to mod the case, will there be a noticable difference between a small radiator and no shroud vs 2+ or a big radiator and shroud?

I'm assuming by "2+", you mean 2 small radiators w/o shrouds. If so, you might not see much difference with a second small rad w/o shroud due to the decrease in flow you'll get. A big rad w/shroud will allow more heat to be shed with about as much resistance as the single small rad. Basicly, you'll get what you pay/work for...

i hope i get what i waork for, i'm working my little ^&* off trying to get my WC done...

Why try if youre just going to be an average lazy teenager and not put in any effort and then complain when you get bad results.

First, I understand not modding your case but i highly reccommend using a shroud it will seriously effect your performance if you don't. Second, If you use two small rads you'll need to get a strong pump. like an ehiem 1250 or a danger den D4.

I have a shroud, and also there was a time when the same exact setup didnt have a shroud.

Without the shroud, my idle cpu was 36 and load was around 45.
With the shroud, i'm idle 29 and load 32-33.

I've said it before, and I'll say it again, shrouds are NOT optional. Not only does it severely impact performance (due the dead spot in the middle of your fan being pressed against the radiator), but it also makes your radiator fan run MUCH louder because it has to work so much harder. HiProfile is right, 2 rads is a no no without a strong pump. On my first WC setup, I had a high flow trans cooler for my main radiator, then I decided to add a BI Micro to the loop when I put in my GPU block. Big mistake. My poor little Eheim 1048 about had a heart attack, and my temps actually got worse. Of course I attributed it to having added the heat from the GPU. Well one day it occured to me that I wasn't getting much flow in my system, so I pulled the BI Micro. CPU Temps dropped 4C and GPU temps dropped 8C. All because I didn't have pump with enough head pressure to push the water through the loop. And no, two small radiators don't equal one big one. Those micro rads tend to be quite restrictive compared to a regular heater core.