these look like 2 excellent quest mods and I see a lot of people using them.

however, the readme for episode 2 in particular points out that this is not designed to work alongside an heavily modded game.

any advice from people who've used this? I've got a crapload of stuff installed so chances of conflict are probably very high for me :/

for example it seems both dibella's watch and GTA2 master files need to load directly after Oblivion.esm, so I'm pretty sure I'd have to choose between one or the other...

Last time I tried to play GTA2 it was also with a heavily modded game. I even forked over the precious 01 slot to it, only to find that the worldspace most of it should take place on is bugged to hell and back. Nothing visually out of place but the thing was crashing practically every step I took.

GTA 1 was nice and stable, and I really wanted to play GTA 2, but it simply didn't want to be played :/

Yes, you'll have to choose one or the other. The whole mess with LOD landscape svcks, especially since it's correctable by the authors. As I just replied to your post in BOSS

I guess I'll just be happy with episode 1 then, thanx

Well, it seems you had some trouble with getting your load order to work with GTA 2 (as you said, you played with loads of mods.) But it's nothing wrong with the mod itself, I know because I've been playing both and found no bugs from the start to end. But yeah, if you do not load the esm right after oblivion.esm you will experiance major problems.

Well, it's not like you will be able to be in both the worldspace where GTA2 takes place and ie: dibellas watch. So just swap the two depending on your situation.

If your in doubt then I'd advise to leave GTA for your next play through or add it when your current character is almost at it's end.
You've already mentioned that you've a heavy load order so why take the chance of it all blowing up in your face?

I've only added GTA 1, which is a simple stable excellent questmod so no issues here.

GTA 2 can wait