Originally Posted by Tuna2

First off, 18 is stronger than Meta Cooler. She took out two super saiyans simultaneously. In addition, 17 later states that she could've beaten every one of the Z warriors present had she so wished. Meta Cooler was defeated by the combined efforts of SSJ Vegeta and SSJ Goku thus proving that 18>2 super saiyans>Meta Cooler.

In terms of raw power, I'd put Super 13 around the same level as 16. Meta Cooler would probably be a bit above a super saiyan but well below Androids 17 or 18. I'd say it would be a tough call but from what we've seen, no matter how many weaklings you bring together, they will always be beaten by the stronger opponent.