hello,
- When I adjust the speed of a clip in the timeline (make it slower), all clips infront of it get pushed (even though there's enough gap infront of the 1st clip).

1) how do you adjust the speed of a clip, without pushing any other clips from their original place?

- Lets say the clips got pushed. So I highlight them all, and drag them back to their original place (using the arrow tool).
If there are no transitions between the clips, they get moved fine. But, if I have applied transitions between the clips, and tried to highlight everything (clips + transition), and drag them, they will get messed up!! transitions will be shorter, clips get trimmed.

2) How do you I move clips with transitions around?

Thanx in advance!

If it moved everything else, insert a slug in the blank space by control clicking and selecting "fill with slug", then shift delete (ripple delete) the slug. It will pull everything after it closed.
It would be easier to change the speed in a separate sequence and drop the sequence into the timeline (called nesting). If you change the duration of a clip by adjusting speed, it thinks the empty space is supposed to be there and shifts it as well, just in case you had the empty space on a different layer and it was supposed to be empty.

I'm not sure what's going on with your transitions but I've seen strange things like that before. My habit now is to do the rough cut with NO transitions and then go back when it's all cut and apply transitions where I need them. It seems a little faster because I don't have to render anything after I make changes and I can watch the "almost" final production and feel what transitions will work better with the pacing.

yeah, that's what I'm doing right now. But I thought there was an easier way.
In Adobe Premiere, if you change the speed of a video (and there's another clip right next to it), it will not push anything; it will preserve the duration.
I just wish FCP had the option for that. Makes it easier than switching timelines.

I'm curious, how could it preserve the duration and change the speed? It's either going to add frames or cut frames out, both of which will change the duration of the clip. Maybe it just slid the whole sequence over for you so you didn't notice the change.
It's kind of a catch 22. If it didn't slide the video you would have the problem you currently experience, if it did, then you (or it) would have to decide whether to slide the whole timeline and ALL of the layers or just the current layer which, if you had other shots on different layers it would wreak havoc on the whole timeline because you would have to realign everything again OR it would have to magically decide which clip to cut or expand to retain the overall running time.
I have a piece where the image swaps between slow-mo and real-time. The shots are on two different layers with real-time on the top layer and slow-mo on the bottom layer. If I change the speed of the bottom layer, the clip grows or shrinks accordingly but doesn't affect the top layer. Now if I were to change the speed of one of the clips in the top layer it would shift everything after it over because it sees these empty spaces as part of the final edit. It makes me a little crazy at times but I have learned to adjust my work flow to accommodate it. Now if I need to do this I set a marker at the original final duration limit of the clip, change the speed, blade the marked spot and shift delete the extra footage. This allows the speed change to expand the footage and thus shift the timeline, and shift+delete will delete and close the gap returning the timeline to it's original timing.
It might just take a little experimenting to find a decent method that works for you and it seems to be a little different on each project.
-good luck!