Go overboard vs be carried away

[James Cho]

What is the difference in meaning between 'don't get carried away!' and 'don't go overboard!'?

Eg., You choose a banana tree costume for a party and your friend will say, "Don't get carried away. Why not just a Napoleon uniform?

Can I replace 'don't get carried away' with 'don't go overboard' in this sentence?

 

[Bigote Blanco]

I believe in this context they are interchangable. Yes, you can replace it.

 

[Cypherpunk]

They would mean the same thing, in this case. I think 'getting carried away' tends to have the connotation that one has worked on something so hard or so long that it has become much more than was originally envisioned. 'Going overboard' tends to convey that idea that one has tried, from the beginning, to come up with an idea that is really outrageous and wilder than anything anyone else will try.