http://www.readymaderc.com/store/
http://www.urbandrones.com/
https://hobbywireless.com/
in that order for me. there is also bevrc.com, foxtech.com, but there chineese and even when there right there for you, it takes a month to get anything back to them for credit or exchange so in my eyes, it negates most of the CS.
assuming you have a 2.4 type rc control, i'd go with an immersion 5.8 600mw vtx and an 5.8 uno receiver. it doesn't have the best non line of site, but it aint bad unless you want to fly through the forest. if your able to get over the forest, your golden. the 1.2 and 1.3 are powerful, but honestly unless you can get the lawmate vtx's, it's a waste of time. the parts inside these others are super succeptable to interferrence. the immersion stuff is made for rc vehicles, lawmate is a surveilance camera parts............. After that all you need is a 2.5 mm a/v cable to hook into your gopro, readymade has one that snaps in for ya and has a 90 degree elbow so it's not sticking straight out the side then you need a monitor. Anything with a/v inputs or the yellow, red and white. I don't bother transmitting the audio unless i want to know how the signal is as in i won't hook a mic to it, but i'll hook my receivers audio to my tv, you hear static right before the image goes bad so you get a warning
the data you speak of is called OSD or on screen display. There are alot of em, but again, the immersion is very easy, plugs inline with your camera with cables supplied, then if you get into a more solid link, not necesarily to fly further, but so you don't loose it to a cheap 2.4 rc connection, the EzUHF by immersion goes inbetween em all and gives you good data like how well your radio is linked to the craft in percentage realtime, etc.
