The brightness will not really differ between the two concerning the brightness depends on the bulbs you get and if you grind the CCFL shield or whatever the heck it's called. I really liked the spec D's but they tended to bounce on me when going down a bumpy road. Hence why I switched back to stocks. I would take a serious look at the projectors offered in the limited site vendor. I will get name hang on.
In my experience with the Spec-D's if you go down a lot of gravel roads I wouldnt suggest them. I have had them on for ~50k miles and they lens are gone. I tried restoring them, but they just scratch to easily.
I have the SpecD headlights. The bulbs that came in them are crap. I bought better Silvania bulbs shortly after installing the headlights. I made a How-To on how to make new bulbs the the Halos if your wanting to change the color. The covering for the connectors isnt the best and have had them short out on the low beams. Replaced them and put better heat shirink on them.