Well, it turns out the the Shelby/Kicker 8" subs are just slightly modified Kicker CompVT's. The install place said they just took the plastic backing off. I picked up my baby today and when I walked in the guy said "Loudest door speakers ever..." They sound amazing! He paired them with an Alpine PDR-F50
4-channel amp and Alpine SPR-68
6x8's and went nuts on the doors with Dynamat. We went with the 4-chanel amp in case I ever want to add another sub in the trunk down the road, but I don't imagine ever needing it. I can't believe how clear the sound is. I've honestly never been in a car that sounded so nice, even remembering my days back in the late 90's with 2 12" subs in the trunk.
I've read mixed reviews on the Shelby/Kicker 8's, so I was a little nervous. I've read that they "aren't as loud as the stock subs," or aren't crisp-sounding. Not sure what those folks heard, but if you put them on a nice amp with a good aftermarket head unit they sound fracking amazing. And I have ears that are overly sensitive to higher pitches. I don't need to set off car alarms with my system (I grew out of that 15 years ago), but I do like to listen to my music loud. I listen to multiple genres, from classic rock to goth metal to dubstep and it all sounds amazing.
I would recommend them to anybody who is curious about them. It's a shame there isn't much info online about them. Even the install guy couldn't find much.