Inviting Countries to Your Common Market (Kebir Blue)

I'm wondering about a regional common market including some neighboring countries with negative profit/loss. Should this be a REAL concern? Specifically, will it negatively affect the economies of the other CM members? And how so?

Their economy shouldnt effect anything. Common markets are just a contract processing center. Only thing might go wrong is they cant fufil all the contract so you may need to go to world market.
Careful how you use common markets, remember, anything you sell on contract you arent making a mark up over the going price, so like you cant charge 250 for 220Q products, only 220.

But that in turn saves me money on products I purchase, correct? Also, get more secure supply than say the world market can supply on FMUs, etc?

You can. OK this is only the way I do it, there are many others: See, mostly you wont want to buy anything at top quality (300 ish), your country should buy at 100 and your upgraded corps probably about 160, less than 200 anyway. And to add into this equation that most corps will need to produce at high quality to make a profit, you get the paradox of either paying far too much for your home grown product or your corps get cheaper supply but cant make much profit. I doubt you will get all you need or sell all you make in a common market so the profit to be made through selling on the world market has been sacrificed. (Am I making sense ?). Basically not many people, especially new people, make much profit by using contracts of any sort.
There are ways of getting it to work by selective supply to your corps, eg. low quality expensive things your corp uses a lot of and high quality cheap things, so the average supply quality is abou