PCI Express and USB dongle connection versus board integration

we are thinking of designing an embedded design which includes wireless technologies such as WiFi, 3G and Bluetooth. we are thinking to do new PCB board by integrating wireless modules in it. however, some ppl in the team believes that buying controller board (EBOX) and connect wireless modules in USB dongles and PCI Express cards will save cost and time.

i'm trying to explain in terms of RF e.g. radio collocation issue but they need solid explanation on why we have to design embedded board and not buy controller board (EBOX) and connect wireless dongles and PCI express card. any body have better explanation? all the replies after appreciated.

i have attached datasheet of controller board (EBOX) and usb dongle (WiFi) which they are looking at.

any link which explains the topic also welcomed!

I don't know what country you are in. If you make a radio you will have to fight to get it government approved. Look at the cost of that. Get a quote.

Some times it is good to use a designed board to get up and running fast with out so much government approvals. Then if production is large go back and do a cost down design when you have more time.

hi ronsimpson,
im aware of certification requirements. what im expecting is performance difference between PCI express & USB dongle versus board integration. im sure board integration is between in terms of RF performance. but why is it better? how to explain this or proof this?