new pics of rear disc brakes!

Thats how they should have came from the factory. At least.
Now you need to get some fancy rotors for the front and you should've thrown some 73mm calipers on the front while you were at it.

Would those happen to be vented rotors?
 
I had a boss once who was an old Chilean man and his best advice was "Work once, not twice"

Now you have rear discs, but this will all soon be ditched for an upgraded 5-lug setup, no?

Hopefully he thought of that already and is happy with converting to discs in the rear and keeping the 4-lug set up.

I plan on doing the same thing. Mine is a strong-running street car with no plans for track time (convertible) so I'd be quite content upgrading the rears to disc, possibly upgrading the fronts to a larger/better set up and keeping my 4 lug Pony's or going with the 4-lug Cobra Rs (like pictured - I don't share others' despise for them - I like them).

Since I'm not competing, just enhancing the car's braking capabilities with set-ups like this will work fine for me. I can then use the money that would be used for converting to 5-lug along with the money required for the subsequent new rims/tires toward more suspsension items or engine stuff.

To the OP: congrats - nice set up! You'll enjoy the better braking with the rear discs!!!